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Gauge invariance and the physical spectrum in the two-Higgs-doublet
model: Observable states are gauge-invariant. In a non-Abelian gauge theory, these
are necessarily composite operators. We investigate the spectrum of these
operators in the two-Higgs-doublet model. For this purpose, we are working
along the lines of the Fr\"ohlich-Morchio-Strocchi mechanism to relate the
physical spectrum to the spectrum of the elementary particles. We also
investigate the consequences of spontaneous breaking of the global (custodial)
symmetry group. Finally, we briefly comment on how to test the results using
lattice methods. | hep |
Topology of Minimal Walking Technicolor: We perform a lattice study of the topological susceptibility and instanton
size distribution of the $\su{2}$ gauge theory with two adjoint Dirac fermions
(also known as Minimal Walking Technicolor), which is known to be in the
conformal window. In the theory deformed with a small mass term, by drawing a
comparison with the pure gauge theory, we find that topological observables are
decoupled from the fermion dynamics. This provides further evidence for the
infrared conformality of the theory. A study of the instanton size distribution
shows that this quantity can be used to detect the onset of finite size
effects. | hep |
Gauged $B - 3 L_τ$ and Baryogenesis: It has recently been shown that by extending the minimal standard model to
include a right-handed partner to $\nu_\tau$, it is possible to gauge the $B -
3 L_\tau$ quantum number consistently. If we add two scalar triplets, one
trivial ($\xi_1$) and one nontrivial ($\xi_2$) under $B - 3 L_\tau$, it is
possible also to have desirable neutrino masses and mixing for neutrino
oscillations. At the same time, a lepton asymmetry can be generated in the
early universe through the novel mechanism of the decay of the heavier $\xi_1$
into the lighter $\xi_2$ plus a neutral singlet ($\zeta^0$). This lepton
asymmetry then gets converted into a baryon asymmetry at the electroweak phase
transition. | hep |
Energy Correlators Taking Charge: The confining transition from asymptotically free partons to hadrons remains
one of the most mysterious aspects of Quantum Chromodynamics. With the wealth
of high quality jet substructure data we can hope to gain new experimental
insights into the details of its dynamics. Jet substructure has traditionally
focused on correlations, $\langle \mathcal{E}(n_1) \mathcal{E}(n_2) \cdots
\mathcal{E}(n_k) \rangle$, in the energy flux of hadrons. However,
significantly more information about the confinement transition is encoded in
how energy is correlated between hadrons with different quantum numbers, for
example electric charge. In this Letter we develop the field theoretic
formalism to compute general correlations, $\langle \mathcal{E}_{R_1}(n_1)
\mathcal{E}_{R_2}(n_2) \cdots\mathcal{E}_{R_k}(n_k) \rangle$, between the
energy flux carried by hadrons with quantum numbers $R_i$, by introducing new
universal non-perturbative functions, which we term joint track functions.
Using this formalism we show that the strong interactions introduce enhanced
small angle correlations between opposite-sign hadrons, relative to like-sign
hadrons, identifiable as an enhanced scaling of $\langle \mathcal{E}_+(n_1)
\mathcal{E}_-(n_2) \rangle$ relative to $\langle \mathcal{E}_+(n_1)
\mathcal{E}_+(n_2) \rangle$. We are also able to compute the scaling of a
$C$-odd three-point function, $\langle \mathcal{E}_\mathcal{Q}(n_1)
\mathcal{E}_\mathcal{Q}(n_2) \mathcal{E}_\mathcal{Q}(n_3) \rangle$. Our results
greatly extend the class of systematically computable jet substructure
observables, pushing perturbation theory deeper into the parton to hadron
transition, and providing new observables to understand the dynamics of
confinement. | hep |
Three dimensional fermionic determinants, Chern-Simons and nonlinear
field redefinitions: The three dimensional abelian fermionic determinant of a two component
massive spinor in flat euclidean space-time is resetted to a pure Chern-Simons
action through a nonlinear redefinition of the gauge field. | hep |
The effect of higher dimensional QCD operators on the spectroscopy of
bottom-up holographic models: Within the bottom-up holographic approach to QCD, the highly excited hadrons
are identified with the bulk normal modes in the fifth "holographic" dimension.
We show that additional states in the same mass range can appear also from
taking into consideration the 5D fields dual to higher dimensional QCD
operators. The possible effects of these operators were not taken into account
in almost all phenomenological applications. Using the scalar case as the
simplest example, we demonstrate that the additional higher dimensional
operators lead to a large degeneracy of highly excited states in the Soft Wall
holographic model while in the Hard Wall holographic model, they result in a
proliferation of excited states. The considered model can be viewed as the
first analytical toy-model predicting a one-to-one mapping of the excited meson
states to definite QCD operators to which they prefer to couple. | hep |
A Search For the Higgs Boson in CMS in the Two Photon Decay Channel: We report on a search for SM Higgs Boson in the two photon decay mode
conducted by the CMS experiment with the data accumulated during the 2010 &
2011 running of the LHC at center of mass collision energy of 7 TeV. | hep |
Asymptotic Scale Invariance and its Consequences: Scale invariance supplemented by the requirement of the absence of new heavy
particles may play an important role in addressing the hierarchy problem. We
discuss how the Standard Model may become scale invariant at the quantum level
above a certain value of the Higgs field value without addition of new degrees
of freedom and analyze phenomenological and cosmological consequences of this
setup, in particular, possible metastability of the electroweak vacuum and
Higgs inflation. | hep |
Spacetime models, fundamental interactions and noncommutative geometry: We discuss the problem of determining the spacetime structure. We show that
when we are using only topological methods the spacetime can be modelled as an
R- or Q-compact space although the R-compact spaces seem to be more
appropriate. Demanding the existence of a differential structure substantially
narrows the choice of possible models. The determination of the differential
structure may be difficult if it is not unique. By using the noncommutative
geometry construction of the standard model we show that fundamental
interactions determine the spacetime in the class of R-compact spaces. Fermions
are essential for the process of determining the spacetime structure. | hep |
String Theory Bounds on the Cosmological Constant, the Higgs mass, and
the Quark and Lepton Masses: We elaborate on the new understanding of the cosmological constant and the
gauge hierarchy problems in the context of string theory in its metastring
formulation, based on the concepts of modular spacetime and Born geometry. The
interplay of phase space (and Born geometry), the Bekenstein bound, the mixing
between ultraviolet (UV) and infrared (IR) physics and modular invariance in
string theory is emphasized. This new viewpoint is fundamentally rooted in
quantum contextuality and not in statistical observer bias (anthropic
principle). We also discuss the extension of this point of view to the problem
of masses of quarks and leptons and their respective mixing matrices. | hep |
From N=2 Fermionic Strings to Superstrings?: I review the covariant quantization of the critical $N{=}2$ fermionic string
with and without a global ${\bf Z}_2$ twist. The BRST analysis yields massless
bosonic and fermionic vertex operators in various ghost and picture number
sectors, as well as picture-changers and their inverses, depending on the field
basis chosen for bosonization. Two distinct GSO projections exist, one
(untwisted) retaining merely the known bosonic scalar and its spectral-flow
partner, the other (twisted) yielding two fermions and one boson, on the
massless level. The absence of interactions in the latter case rules out
standard spacetime supersymmetry. In the untwisted theory, the
$U(1,1)$-invariant three-point and vanishing four-point functions are confirmed
at tree level. I comment on the $N{=}2$ string field theory, the integration
over moduli and the realization of spectral flow. | hep |
Integrability and Scheme-Independence of Even Dimensional Quantum
Geometry Effective Action: We investigate how the integrability conditions for conformal anomalies
constrain the form of the effective action in even-dimensional quantum
geometry. We show that the effective action of four-dimensional quantum
geometry (4DQG) satisfying integrability has a manifestly diffeomorphism
invariant and regularization scheme-independent form. We then generalize the
arguments to six dimensions and propose a model of 6DQG. A hypothesized form of
the 6DQG effective action is given. | hep |
Renormalization of a model for spin-1 matter fields: In this work, the one-loop renormalization of a theory for fields
transforming in the $(1,0)\oplus(0,1)$ representation of the Homogeneous
Lorentz Group is studied. The model includes an arbitrary gyromagnetic factor
and self-interactions of the spin 1 field, which has mass dimension one. The
model is shown to be renormalizable for any value of the gyromagnetic factor. | hep |
Nucleon form factors: From the space-like to the time-like region: I discuss how dispersion relations can be used to analyse the nucleon
electromagnetic form factors, with particular emphasis on the constraints from
unitarity and pQCD. Results for nucleon radii, vector-meson couplings, the
onset of pQCD and bounds on the strangeness form factors are presented. The em
form factors in the time-like region reveal some interesting physics which is
not yet understood in full detail. The need for a better data basis at low,
intermediate and large momentum transfer and also in the time-like region is
stressed. | hep |
From lightcone actions to maximally supersymmetric amplitudes: In this article actions for N=4 SYM and N=8 supergravity are formulated in
terms of a chiral superfield, which contains only the physical degrees of
freedom of either theory. In these new actions, which originate from the
lightcone superspace, the supergravity cubic vertex is the square of the gauge
theory one (omitting the color structures). Amplitude calculations using the
corresponding Feynman supergraph rules are tedious, but can be simplified by
choosing a preferred superframe. Recursive calculations of all MHV amplitudes
in N=4 SYM and the four-point N=8 supergravity amplitude are shown to agree
with the known results and connections to the BCFW recursion relations are
pointed out. Finally, the new path integrals are discussed in the context of
the double-copy property relating N=4 SYM theory to N=8 supergravity. | hep |
Gravitational Wave from Axion-SU(2) Gauge Fields: Effective Field Theory
for Kinetically Driven Inflation: Building on Weinberg's approach to effective field theory for inflation, we
construct an effective Lagrangian for a pseudo scalar (axion) inflaton field
with shift symmetry. In this Lagrangian we allow the axion field to couple to
non-Abelian gauge fields via a Chern-Simons term. We then analyze a class of
inflation models driven by kinetic terms. We find that the observational
constraints on the amplitudes of curvature perturbations and non-Gaussianity
yield a lower bound for the tensor-to-scalar ratio of $r\gtrsim 5\times
10^{-3}$ from the vacuum fluctuation. The sourced gravitational wave from SU(2)
gauge fields further increases the tensor-to-scalar ratio and makes the total
gravitational wave partially chiral and non-Gaussian, which can be probed by
polarization of the cosmic microwave background and direct detection
experiments. We discuss constraints on parameter space due to backreaction of
spin-2 particles produced by the gauge field. | hep |
Topological B-model and ${\hat c}=1$ String Theory: We study the topological B-model on a deformed $\Z_2$ orbifolded conifold by
investigating variation of complex structures via quantum Kodaira-Spencer
theories. The fermionic/brane formulation together with systematic utilization
of symmetries of the geometry gives rise to a free fermion realization of the
amplitudes. We derive Ward identities which solve the perturbed free energy
exactly. We also obtain the corresponding Kontsevich-like matrix model. All
these confirm the recent conjecture on the connection of the theory with ${\hat
c}=1$ type 0A string theory compactified at the radius $R=\sqrt{\alpha'/2}$. | hep |
Pair structure of heavy tetraquark systems: We study the pair description of heavy tetraquark systems $|QQ\bar Q \bar
Q\rangle$ in the frame of a non-relativistic potential model. By taking the two
heavy quark pairs $(Q\bar Q)$ as colored clusters, the four-quark Schr\"odinger
equation is reduced to a two-pair equation, when the inner motion inside the
pairs can be neglected. Taking into account all the Casimir scaling potentials
between two quarks and using the lattice QCD simulated mixing angle between the
two color-singlet states for the tetraquark system, we extracted a detailed
pair potential between the two heavy quark pairs. | hep |
Connection Between $ν_e, ν_μ, ν_τ$ and $ν_1, ν_2, ν_3$
Neutrino States and Time Dependence of Neutrino Wave Functions and Transition
Probabilities at Three Neutrino Oscillations in Vacuum: For description of the $d, s, b$ quark mixings the Cabibbo-Kobayashi-Maskawa
matrices are used but they do not contain the time dependence. In this work the
analogous matrix is obtained for the case of three neutrino ($\nu_{e}, \nu_{\mu
}, \nu_{\tau}$) mixings (oscillations) in vacuum in the general case, when CP
violation is absent. In contrast to the quark case this matrix contains the
time dependence. The matrix for probability of neutrino transitions
(oscillations) in vacuum is also obtained. Naturally, it contains the time
dependence. The matrix which does not contain the time dependence is obtained
by using time $t$ averaging of this matrix. Elements of this matrix can be used
to describe neutrino decays. | hep |
Parametric Amplification of Gravitational Fluctuations During Reheating: We demonstrate that cosmological perturbations can undergo amplification by
parametric resonance during the preheating period following inflation, even on
scales larger than the Hubble radius, without violating causality. A unified
description of gravitational and matter fluctuations is crucial in order to
determine the strength of the instability. To extract specific signatures of
the oscillating inflaton field during reheating, it is essential to focus on a
variable describing metric fluctuations which is constant in the standard
analyses of inflation. When doing this in the case of a massive inflaton
without self coupling, we find no additional growth of super-horizon modes
during reheating beyond what the usual analyses of the growth of fluctuations
predict. However, for a massless self coupled inflaton, there is an initial
increase in the value of the gravitational potential, which may lead to
different predictions for observations. | hep |
Topological Amplitudes and the String Effective Action: In this work, we study a class of higher derivative couplings in the string
effective action arising at the junction of topological string theory and
supersymmetric gauge theories in the $\Omega$-background. They generalise a
series of gravitational couplings involving gravitons and graviphotons, which
reproduces the topological string theory partition function. The latter
reduces, in the field theory limit, to the partition function of the gauge
theory in the $\Omega$-background when one if its parameters, say $\epsilon_+$,
is set to zero. This suggests the existence of a one-parameter extension called
the refined topological string. The couplings considered in this work involve
an additional vector multiplet and are evaluated, perturbatively and
non-perturbatively, at the string level. In the field theory limit, they
correctly reproduce the partition function of the gauge theory in a general
$\Omega$-background. Hence, these couplings provide new perspectives toward a
worldsheet definition of the refined topological string. | hep |
Reflection Factors for the Principal Chiral Model: We consider the SU(2) Principal Chiral Model (at level $k=1$) on the
half-line with scale invariant boundary conditions. By looking at the IR
limiting conformal field theory and comparing with the Kondo problem, we
propose the set of permissible boundary conditions and the corresponding
reflection factors. | hep |
Reconstructing charged particle track segments with a quantum-enhanced
support vector machine: Reconstructing the trajectories of charged particles from the collection of
hits they leave in the detectors of collider experiments like those at the
Large Hadron Collider (LHC) is a challenging combinatorics problem and
computationally intensive. The ten-fold increase in the delivered luminosity at
the upgraded High Luminosity LHC will result in a very densely populated
detector environment. The time taken by conventional techniques for
reconstructing particle tracks scales worse than quadratically with track
density. Accurately and efficiently assigning the collection of hits left in
the tracking detector to the correct particle will be a computational
bottleneck and has motivated studying possible alternative approaches. This
paper presents a quantum-enhanced machine learning algorithm that uses a
support vector machine (SVM) with a quantum-estimated kernel to classify a set
of three hits (triplets) as either belonging to or not belonging to the same
particle track. The performance of the algorithm is then compared to a fully
classical SVM. The quantum algorithm shows an improvement in accuracy versus
the classical algorithm for the innermost layers of the detector that are
expected to be important for the initial seeding step of track reconstruction. | hep |
Strangelets -- Effects of Finite Size and Exact Color Singletness: Matter consisting of up, down and strange quarks, socalled Strange Quark
Matter, has been hypothesized to be stable in bulk, and conceivably stable or
metastable in finite systems---strangelets---as an alternative state to
ordinary baryonic matter. Strangelets, if they exist, may be relics from the
hot and dense early universe, or they could be produced in high energy events,
such as collisions of heavy nuclei at relativistic speeds. This thesis
investigates the implications of various effects that affects the possible
(meta-) stability of strangelets, such as finite size, distribution of quark
states (shell model), interaction with a hadron gas, non-zero temperature and
QCD constraints of color singletness of the wave function. These effects are
studied within the phenomenological MIT bag model of quark matter using the
multiple reflection expansion for a liquid drop model equation of state with
comparison to a shell model. Finite size, non-zero temperature and color
singlet constraints have a destabilizing effect on strangelets, and can
suppress their production in heavy ion collisions.
The work presented has been described in part in the following publications:
Dan M{\o}nster Jensen and Jes Madsen, Strangelets at Non-Zero Temperature, in
Strangeness and Quark Matter, edited by G. Vassiliadis, A. D. Panagiotou, S.
Kumar, and J. Madsen (World Scientific, Singapore, 1995), pp. 220--229.
Jes Madsen, Dan M. Jensen, and Michael B. Christiansen, Color Singlet
Suppression of Quark-Gluon Plasma Formation, Phys. Rev. C 53, 1883 (1996).
Dan M. Jensen and Jes Madsen, Strangelets with Finite Entropy, Phys. Rev. D
53, R4719 (1996).
Dan M{\o}nster Jensen, Jes Madsen, and Michael B. Christiansen, Color Singlet
Strangelets, Heavy Ion Phys. 4 (1-4), 387-394 (1996). | hep |
Assisted Contraction: We consider the dynamics of a contracting universe ruled by two minimally
coupled scalar fields with general exponential potentials. This model describes
string-inspired scenarios in the Einstein frame. Both background and
perturbations can be solved analytically in this model. Curvature perturbations
are generated with a scale invariant spectrum only for a dust-like collapse, as
happens for a single field model with an exponential potential. We find the
conditions for which a scale invariant spectrum for isocurvature perturbation
is generated. | hep |
Effect of spatial fluctuations on the scaled factorial moments in
second-order quark-hadron phase transition within Ginzburg-Landau description: The scaled factorial moments in second-order quark-hadron phase transition
are reexamined within the Ginzburg-Landau description, with the spatial
fluctuations of phase angle of the complex field $\phi$ taken into account
rigorously. Scaling behaviors between $F_q$ and $F_2$ are shown, and the
exponent $\nu$ is found very close to the one without spatial fluctuations. | hep |
Searches for exotica at LEP: The results of various searches for new physical phenomena beyond the
Standard Model using data from the four LEP experiments are summarized. Topics
presented include the search for flavour-changing neutral currents with single
top production, compositeness leading to the production of excited leptons, and
manifestations of extra dimensions. | hep |
Topological susceptibility in finite temperature (2+1)-flavor QCD using
gradient flow: We compute the topological charge and its susceptibility in finite
temperature (2+1)-flavor QCD on the lattice applying a gradient flow method.
With the Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson
quarks, we perform simulations on a fine lattice
with~$a\simeq0.07\,\mathrm{fm}$ at a heavy $u$, $d$ quark mass with
$m_\pi/m_\rho\simeq0.63$ but approximately physical $s$ quark mass with
$m_{\eta_{ss}}/m_\phi\simeq0.74$. In a temperature range
from~$T\simeq174\,\mathrm{MeV}$ ($N_t=16$) to $697\,\mathrm{MeV}$ ($N_t=4$), we
study two topics on the topological susceptibility. One is a comparison of
gluonic and fermionic definitions of the topological susceptibility. Because
the two definitions are related by chiral Ward-Takahashi identities, their
equivalence is not trivial for lattice quarks which violate the chiral symmetry
explicitly at finite lattice spacings. The gradient flow method enables us to
compute them without being bothered by the chiral violation. We find a good
agreement between the two definitions with Wilson quarks. The other is a
comparison with a prediction of the dilute instanton gas approximation, which
is relevant in a study of axions as a candidate of the dark matter in the
evolution of the Universe. We find that the topological susceptibility shows a
decrease in $T$ which is consistent with the predicted $\chi_\mathrm{t}(T)
\propto (T/T_{\rm pc})^{-8}$ for three-flavor QCD even at low temperature
$T_{\rm pc} < T\le1.5 T_{\rm pc}$. | hep |
Towards a unified theory of the fundamental physical interactions based
on the underlying geometric structure of the tangent bundle: This paper pursues the hypothesis that the tangent bundle (TB) with the
central extended little groups of the SO(3,1) group as gauge group is the
underlying geometric structure for a unified theory of the fundamental physical
interactions. Based on this hypothesis as a first step recently I presented a
generalized theory of electroweak interaction which includes hypothetical dark
matter particles (Eur. Phys. J C 79, 779 (2019). The vertical Laplacian of the
tangent bundle possesses the same form as the Hamiltonian of a 2D semiconductor
quantum Hall system. This explains fractional charge quantization of quarks and
the existence of lepton and quark families. As will be shown the SU(3) colour
symmetry for strong interaction arises in the TB as an emergent symmetry
similar as Chern-Simon gauge symmetries in quantum Hall systems. This predicts
a signature of quark confinement as an universal large-scale property of the
Chern-Simon fields and induces a new understanding of the vacuum as the ground
state occupied with a condensate of quark-antiquark pairs. The gap for
quark-antiquark pairing is calculated in the mean-field approximation which
allows a numerical estimation of the characteristic parameters of the vacuum
such as its chemical potential, the quark condensation parameter and the vacuum
energy. Note that previously a gauge theoretical understanding of gravity has
been achieved by considering the translation group T(3,1) in the TB as gauge
group. Therefore the theory presented here can be considered as a new type of
unified theory for all known fundamental interactions linked with the
geometrization program of physics. | hep |
Neutrino and Charged Lepton Flavour Today: Flavour physics is a priceless window on physics beyond the Standard Model.
In particular, flavour violation in the lepton sector looks very promising, as
high precision measurements are prospected in future experiments investigating
on $\mu\rightarrow e$ conversion in atomic nuclei: the predictions for this
observable are analysed in the context of the type I Seesaw mechanism.
Furthermore, new ideas to explain the Flavour Puzzle recently appeared, mainly
based on a possible dynamical origin of the Yukawa couplings and on flavour
symmetries. The focus of this proceeding will be set on the Minimal Flavour
Violation ansatz and on the role of the neutrino Majorana character: when an
$O(2)_{N}$ flavour symmetry acts on the right-handed neutrino sector, the
minimum of the scalar potential allows for large mixing angles -in contrast to
the simplest quark case- and predicts a maximal Majorana phase. This leads to a
strong correlation between neutrino mass hierarchy and mixing pattern. | hep |
Observation of $Λ_b^0\rightarrow D^+ p π^-π^-$ and
$Λ_b^0\rightarrow D^{*+} p π^-π^-$ decays: The multihadron decays $\Lambda_b^0\rightarrow D^+ p \pi^-\pi^-$ and
$\Lambda_b^0\rightarrow D^{*+} p \pi^-\pi^-$ are observed in data corresponding
to an integrated luminosity of 3fb$^{-1}$, collected in proton-proton
collisions at centre-of-mass energies of 7 and 8TeV by the LHCb detector. Using
the~decay $\Lambda_b^0\rightarrow \Lambda_c^+ \pi^+ \pi^-\pi^-$ as a
normalisation channel, the ratio of branching fractions is measured to be $$
\frac { {\mathcal{B}} ( \Lambda_b^0\rightarrow D^+ p \pi^-\pi^- ) }
{ {\mathcal{B}} ( \Lambda_b^0\rightarrow \Lambda_c^+ \pi^+ \pi^-\pi^- ) }
\times
\frac { {\mathcal{B}} ( D^+ \rightarrow K^-\pi^+\pi^+) }
{ {\mathcal{B}} ( \Lambda_c^+ \rightarrow p K^-\pi^+ ) }
= ( 5.35 \pm 0.21 \pm 0.16 ) \% \,, $$ where the first uncertainty is
statistical and the second systematic. The ratio of branching fractions for
$\Lambda_b^0\rightarrow D^{*+} p \pi^-\pi^-$ and $\Lambda_b^0\rightarrow D^+ p
\pi^-\pi^-$ decays is found to be $$ \frac{ {\mathcal{B}} (
\Lambda_b^0\rightarrow D^{*+} p \pi^-\pi^- )}
{ {\mathcal{B}} ( \Lambda_b^0\rightarrow D^{+} p \pi^-\pi^- )}
\times
(
{\mathcal{B}}( D^{*+} \rightarrow \pi^0 ) +
{\mathcal{B}}( D^{*+} \rightarrow \gamma ))
= ( 61.3 \pm 4.3 \pm 4.0 ) \% \,. $$ | hep |
Imprints of Cosmic Phase Transition in Inflationary Gravitational Waves: We discuss the effects of cosmic phase transition on the spectrum of
primordial gravitational waves generated during inflation. The energy density
of the scalar condensation responsible for the phase transition may become
sizable at the epoch of phase transition, which significantly affects the
evolution of the universe. As a result, the amplitudes of the gravitational
waves at high frequency modes are suppressed. Thus the gravitational wave
spectrum can be a probe of phase transition in the early universe. | hep |
Fermion scattering on topological solitons in the $\mathbb{CP}^{N-1}$
model: The scattering of Dirac fermions in the background fields of topological
solitons of the $(2+1)$-dimensional $\mathbb{CP}^{N-1}$ model is studied using
analytical and numerical methods. It is shown that the exact solutions for
fermionic wave functions can be expressed in terms of the confluent Heun
functions. The question of the existence of bound states for the
fermion-soliton system is then investigated. General formulae describing
fermion scattering are obtained, and a symmetry property for the partial phase
shifts is derived. The amplitudes and cross-sections of the fermion-soliton
scattering are obtained in an analytical form within the framework of the Born
approximation, and the symmetry properties and asymptotic forms of the Born
amplitudes are investigated. The dependences of the first few partial phase
shifts on the fermion momentum are obtained by numerical methods, and some of
their properties are investigated and discussed. | hep |
Three Roads to Probe-Brane Superconductivity: We study a defect system of two parallel D5 probe branes in a large-N_c D3
background. Using the non-abelian DBI action, we study three different fields
that can give rise to a superconducting phase transition: A vector (p-wave), a
scalar corresponding to a non-trivial "separation"' of the branes in the (3+1)
field theory directions and a scalar corresponding to a separation in the
"internal" S^5 (both s-wave).
Comparing these phases first in the \alpha'^2 expansion, we find that the
internal scalar has the largest critical temperature and is always
thermodynamically preferred. Further, there is an interesting attractor
behavior.
Taking a simplified version of the full DBI action that preserves its
regularity and geometry, we find that the divergences of the \alpha'^2
expansion are resolved and some second order transitions turn into first order
ones. In addition to some other changes of the phase diagram due to the
structure of the DBI action, we observe that the ground state degeneracy of the
unbroken theory is lifted. We also isolate the unphysical artifacts of our
simplification. | hep |
Searches for B0 decays to eta K0, eta eta, eta' eta', eta phi, and eta'
phi: We search for B0 meson decays into two-body combinations of K0, eta, eta',
and phi mesons in 324 million B Bbar pairs collected with the BaBar detector at
the PEP-II asymmetric-energy e+e- collider at SLAC. We measure the following
branching fractions (upper limits at 90% confidence level) in units of 10^{-6}:
Br(B0->eta K0) =1.8+0.7-0.6 +-0.1(2.9), Br(B0->eta eta)=1.1+0.5-0.4 +-0.1(1.8),
Br(B0->eta phi)=0.1+-0.2 +-0.1(0.6), Br(B0->eta' phi)=0.2+0.4-0.3 +-0.1(1.0),
Br(B0->eta' eta')=1.0+0.8-0.6 +-0.1(2.4), where the first error is statistical
and the second systematic. | hep |
$P^Λ_{ψs}(4459)$ and $P^Λ_{ψs}(4338)$ as molecular
states in $ J/ψΛ$ invariant mass spectra: Recently, the LHCb Collaboration has reported two strange hidden-charm
pentaquark states named $P^\Lambda_{\psi s}(4459)$ and $P^\Lambda_{\psi
s}(4338)$ in the $ J/\psi \Lambda$ invariant mass spectra of decays
$\Xi_b^-$$\to$$ J/\psi \Lambda K^-$ and $B^-$$\to$$J/\psi \Lambda
\bar{p}$,respectively. In this work, we perform a coupled-channel study of the
interactions $\Xi_c^*\bar{D}^*$, $\Xi'_c\bar{D}^*$, $\Xi^*_c\bar{D}$,
$\Xi_c\bar{D}^*$, $\Xi'_c\bar{D}$, $\Lambda_c\bar{D}_s^{*}$, $\Xi_c\bar{D}$,
$\Lambda_c\bar{D}_s$, and $\Lambda J/\psi$ in the quasipotential Bethe-Salpeter
equation approach to estimate the $ J/\psi \Lambda$ invariant mass spectra.
With the help of effective Lagrangians, the potential kernel can be constructed
by meson exchanges to obtain the scattering amplitudes, from which the poles of
the bound states and the invariant mass spectra can be reached. The
coupled-channel calculation results in that the width of state
$\Xi_c\bar{D}^{*}(1/2^-)$ is about $18$~MeV and that of state
$\Xi_c\bar{D}^{*}(3/2^-)$ is only about $1.6$~MeV. By comparison with
experimental data, it indicates that the structure $P^{\Lambda}_{\psi s}(4459)$
is mainly from the contribution from the $\Xi_c \bar{D}^{*}(1/2^-)$ state while
the role of state $\Xi_c \bar{D}^{*}(3/2^-)$ cannot be excluded. The line shape
of the structure $P^{\Lambda}_{\psi s}(4338)$ can be reproduced roughly by a
narrow molecular state from the $\Xi_c \bar{D}$ interaction with $J^P$=$1/2^-$,
which is extremely close to the threshold, with a large interference effect.
Besides, an additional state $\Xi'_c \bar{D}(1/2^-)$ is suggested to be
observed as a dip structure in the $J/\psi \Lambda$ invariant mass spectrum. | hep |
Fate of Heavy Quark Bound States inside Quark-Gluon Plasma: Transport equations have been applied successfully to describe the quarkonium
evolution inside the quark-gluon plasma, which include both plasma screening
effects and recombination. We demonstrate how the quarkonium transport equation
is derived from QCD by using the open quantum system framework and effective
field theory. Weak coupling and Markovian approximations used in the derivation
are justified from a separation of scales. By solving the equations
numerically, we study the Upsilon production in heavy ion collisions. | hep |
Discrete Symmetries from Broken $SU(N)$ and the MSSM: In order that discrete symmetries should not be violated by gravitational
effects, it is necessary to gauge them. In this paper we discuss the gauging of
$\Z_N$ from the breaking of a high energy $SU(N)$ gauge symmetry, and derive
consistency conditions for the resulting discrete symmetry fr om the
requirement of anomaly cancellation in the parent symmetry. These results are
then applied to a detailed analysis of the possible discrete symmetries
forbidding proton decay in the minimal supersymmetric standard model. | hep |
Source terms for electroweak baryogenesis in the vev-insertion
approximation beyond leading order: In electroweak baryogenesis the baryon asymmetry of the universe is created
during the electroweak phase transition. The quantum transport equations
governing the dynamics of the plasma particles can be derived in the
vev-insertion approximation, which treats the vev-dependent part of the
particle masses as a perturbation. We calculate the next-to-leading order (NLO)
contribution to the CP-violating source term and CP-conserving relaxation rate,
corresponding to Feynman diagrams for the self-energies with four mass
insertions. We consider both a pair of Weyl fermions and a pair of complex
scalars, that scatter off the bubble wall. We find: (i) The NLO correction
becomes large for $\mathcal O(1)$ couplings. If only the Standard Model (SM)
Higgs obtains a vev during the phase transition, this implies the vev-insertion
approximation breaks down for top quarks. (ii) The resonant enhancement of the
source term and relaxation rate, that exists at leading order in the limit of
degenerate thermal masses for the fermions/scalars, persists at NLO. | hep |
A possible hadronic excess in psi(2S) decay and rho-pi puzzle: We examine the so-called rho-pi puzzle of the psi(2S) decay by incorporating
two inputs: One is the relative phase between the one-photon and the gluon
decay amplitude, and the other is a possible anomaly in the inclusive
nonelectromagnetic decay rate of psi(2S). We propose the possibility that in
the psi(2S) decay a hadronic decay process of long distance origin is important
in addition to the short-distance decay process. The amplitude of this
additional process should nearly cancel the three-gluon amplitude in the
exclusive psi(2S)---> 1-0- and turn the sum dominantly real in contrast to the
J/psi decay. We present general consequences of this mechanism and then briefly
look into two models which possibly explain the course of this additional
amplitude. | hep |
Quantum Anomalies, Running Vacuum and Leptogenesis: an Interplay: We discuss a connection between gravitational-wave physics, quantum theory
anomalies, right-handed (sterile) neutrinos, (spontaneous) CPT Violation and
Leptogenesis, within the framework of string-inspired cosmological models. In
particular, we present a scenario, according to which (primordial)
gravitational waves induce gravitational anomalies during inflation. This, in
turn, results in the existence of an undiluted (at the exit of
inflation/beginning of radiation era) bakcground of the Kalb-Ramond (KR) axion
of the massless bosonic string gravitational multiplet. The latter may violate
spontaneously CP and CPT symmetries, and induce leptogenesis during the
radiation-dominated era in models involving right-handed neutrinos. The
so-generated lepton asymmetry may then be communicated to the baryon sector by
appropriate baryon-minus-lepton-number (B - L)-conserving, but (B +
L)-violating, (sphaleron) processes in the Standard Model sector, thus leading
to matter dominance over antimatter in the Universe.In the current
(approximately de Sitter) era, the KR axion background may provide a source for
an axionic dark matter in the Universe, through its mixing with other axions
that are abundant in string models. As an interesting byproduct of our
analysis, we demonstrate that the anomalies contribute to the vacuum energy
density of the Universe terms of 'running-vacuum' type, proportional to the
square of the Hubble parameter, $H^2$. | hep |
Testing the CP-violating MSSM in stau decays at the LHC and ILC: We study CP violation in the two-body decay of a scalar tau into a neutralino
and a tau, which should be probed at the LHC and ILC. From the normal tau
polarization, a CP asymmetry is defined which is sensitive to the CP phases of
the trilinear scalar coupling parameter $A_\tau$, the gaugino mass parameter
$M_1$, and the higgsino mass parameter $\mu$ in the stau-neutralino sector of
the Minimal Supersymmetric Standard Model. Asymmetries of more than 70% are
obtained in scenarios with strong stau mixing. As a result, detectable CP
asymmetries in stau decays at the LHC are found, motivating further detailed
experimental studies for probing the SUSY CP phases. | hep |
The Case for a Muon Collider Higgs Factory: We propose the construction of a compact Muon Collider Higgs Factory. Such a
machine can produce up to \sim 14,000 at 8\times 10^{31} cm^-2 sec^-1 clean
Higgs events per year, enabling the most precise possible measurement of the
mass, width and Higgs-Yukawa coupling constants. | hep |
Search for New Hadronic Decays of $h_c$ and Observation of
$h_c\rightarrow K^{+}K^{-}π^{+}π^{-}π^{0}$: Ten hadronic final states of the $h_c$ decays are investigated via the
process $\psi(3686)\rightarrow \pi^0 h_c$, using a data sample of $(448.1 \pm
2.9) \times 10^6$ $\psi(3686)$ events collected with the BESIII detector. The
decay channel $h_c\rightarrow K^{+}K^{-}\pi^{+}\pi^{-}\pi^{0}$ is observed for
the first time with a significance of $6.0 \sigma$. The corresponding branching
fraction is determined to be $\mathcal{B}(h_c\rightarrow
K^{+}K^{-}\pi^{+}\pi^{-}\pi^{0}) =(3.3 \pm 0.6 \pm 0.6)\times 10^{-3}$ (the
first uncertainty is statistical and the second systematical). Evidence for the
decays $h_c\rightarrow \pi^{+} \pi^{-} \pi^{0} \eta$ and $h_c\rightarrow
K^{0}_{S}K^{\pm}\pi^{\mp}\pi^{+}\pi^{-}$ is found with a significance of $3.6
\sigma$ and $3.8 \sigma$, respectively. The corresponding branching fractions
(and upper limits) are obtained to be $\mathcal{B}(h_c\rightarrow \pi^{+}
\pi^{-} \pi^{0} \eta ) =(7.2 \pm 1.8 \pm 1.3)\times 10^{-3}$ $(< 1.8 \times
10^{-2})$ and $\mathcal{B}(h_c\rightarrow
K^{0}_{S}K^{\pm}\pi^{\mp}\pi^{+}\pi^{-}) =(2.8 \pm 0.9 \pm 0.5)\times 10^{-3}$
$(<4.7\times 10^{-3})$. Upper limits on the branching fractions for the final
states $h_c \rightarrow K^{+}K^{-}\pi^{0}$, $K^{+}K^{-}\eta$,
$K^{+}K^{-}\pi^{+}\pi^{-}\eta$, $2(K^{+}K^{-})\pi^{0}$,
$K^{+}K^{-}\pi^{0}\eta$, $K^{0}_{S}K^{\pm}\pi^{\mp}$, and
$p\bar{p}\pi^{0}\pi^{0}$ are determined at a confidence level of 90\%. | hep |
A New Class of Non-canonical Conformal Attractors for Multifield
Inflation: We propose a new broad class of multi-field non-canonical inflationary models
as an extension of multi-field conformal cosmological attractors. This also
generalizes the recently discovered class of non-canonical conformal attractors
for single field inflation. Kinetic terms of this class of models are
phenomenologically arising from ${\cal N}=1$ supergravity and from ${\cal N}=1$
superconformal theory, with two conformal scalar compensator fields in the
latter. We show that the inflationary dynamics and predictions of this class of
models are stable with respect to the significant modification of both radial
and angular part of the potential, but it is very sensitive to its minuscule
modification in the geometry of the field space metric. We also show that our
framework can pass the latest observational constraints set by Planck 2018. | hep |
$T\bar{T}$ deformation of chiral bosons and Chern-Simons AdS$_3$ gravity: We study the $T\bar{T}$ deformation of the chiral bosons and show the
equivalence between the chiral bosons of opposite chiralities and the scalar
fields at the Hamiltonian level under the deformation. We also derive the
deformed Lagrangian of more generic theories which contain an arbitrary number
of chiral bosons to all orders. By using these results, we derive the
$T\bar{T}$ deformed boundary action of the AdS$_3$ gravity theory in the
Chern-Simons formulation. We compute the deformed one-loop torus partition
function, which satisfies the $T\bar{T}$ flow equation up to the one-loop
order. Finally, we calculate the deformed stress tensor of a solution
describing a BTZ black hole in the boundary theory, which coincides with the
boundary stress tensor derived from the BTZ black hole with a finite cutoff. | hep |
D-brane Spectrum and K-theory Constraints of D=4, N=1 Orientifolds: We study the spectrum of stable BPS and non-BPS D-branes in Z_2 x Z_2
orientifolds for all choices of discrete torsion between the orbifold and
orientifold generators. We compute the torsion K-theory charges in these D=4,
N=1 orientifold models directly from worldsheet conformal field theory, and
compare with the K-theory constraints obtained indirectly using D-brane probes.
The K-theory torsion charges derived here provide non-trivial constraints on
string model building. We also discuss regions of stability for non-BPS
D-branes in these examples. | hep |
On supersymmetry algebra based on a spinor-vector generator: We study the unitary representation of supersymmetry (SUSY) algebra based on
a spinor-vector generator for both massless and massive cases. A systematic
linearization of nonlinear realization for the SUSY algebra is also discussed
in the superspace formalism with a spinor-vector Grassmann coordinate. | hep |
Modeling small dark energy scale with quintessential pseudoscalar boson: Democracy among the same type of particles is a useful paradigm in studying
masses and interactions of particles with supersymmetry(SUSY) or without SUSY.
This simple idea predicts the presence of massless particles. We attempt to use
one of these massless pseudoscalar particles as generating the cosmological
dark energy(DE) potential. To achieve the extremely shallow potential of DE,
the pseudoscalar boson is required not to couple to the QCD anomaly. So, we
consider two pseudoscalars, one coupling to the QCD anomaly (i.e. QCD axion)
and the other not coupling to the QCD anomaly. To obtain these two
pseudoscalars, we introduce two approximate global U(1) symmetries to realize
them as the pseudo-Goldstone bosons of the spontaneously broken U(1)'s. These
global symmetries are dictated by a gravity respected discrete symmetry.
Specifically, we consider an S2(L) X S2(R) X Z(10R) example, and attempt to
obtain the DE scale in terms of two observed fundamental mass scales, the grand
unification scale M(G) and the electroweak scale v(ew). | hep |
3D Supergravity from wrapped D3-branes: AdS_3 solutions dual to N = (0,2) SCFTs arise when D3-branes wrap Kahler
two-cycles in manifolds with SU(4) holonomy. Here we review known AdS_3
solutions and identify the corresponding three-dimensional gauged
supergravities, solutions of which uplift to type IIB supergravity. In
particular, we discuss gauged supergravities dual to twisted compactifications
on Riemann surfaces of both N=4 SYM and N =1 SCFTs with Sasaki-Einstein duals.
We check in each case that c-extremization gives the exact central charge and R
symmetry. For completeness, we also study AdS_3 solutions from intersecting
D3-branes, generalise recent KK reductions of Detournay & Guica and identify
the underlying gauged supergravities. Finally, we discuss examples of
null-warped AdS_3 solutions to three-dimensional gauged supergravity, all of
which embed in string theory. | hep |
QCD at Low Energies: The modern status of basic low energy QCD parameters is reviewed. It is
demonstrated, that the recent data allows one to determine the light quark mass
ratios with an accuracy 10-15%. The general analysis of vacuum condensates in
QCD is presented, including those induced by external fields. The QCD coupling
constant alpha_s is found from the tau-lepton hadronic decay rate. V-A spectral
functions of tau-decay are used for construction of the V-A polarization
operator Pi_{V-A}(s) in the complex s-plane. The operator product expansion
(OPE) is used up to dimension D=10 and the sum rules along the rays in the
complex s-plane are constructed. The best values of quark condensate and
alpha_s<0|qq|0>^2 are found. The value of quark condensate is confirmed by
considering the sum rules for baryon masses. Gluon condensate is found in four
ways: by considering of V+A polarization operator based on the tau-decay data,
by studying the sum rules for polarization operators momenta in charmonia in
vector, pseudoscalar and axial channels. All of these determinations are in
agreement and result in <(alpha_s/pi)G^2 > =0.005 \pm 0.004 GeV^4. Valence
quark distributions in proton are calculated in QCD using the OPE in proton
current virtuality. The quark distributions agree with those found from the
deep inelastic scattering data. The same value of gluon condensate is favoured. | hep |
Asymptotic Structure of Einstein-Maxwell-Dilaton Theory and Its Five
Dimensional Origin: We consider Einstein-Maxwell-dilaton theory in four dimensions including the
Kaluza-Klein theory and obtain the general asymptotic solutions in Bondi gauge.
We find that there are three different types of news functions representing
gravitational, electromagnetic, and scalar radiations. The mass density at any
angle of the system can only decrease whenever there is any type of news
function. The solution space of the Kaluza-Klein theory is also lifted to five
dimensions. We also compute the asymptotic symmetries in both four dimensional
Einstein-Maxwell-dilaton theory and five dimensional pure Einstein theory. We
find that the symmetry algebras of the two theories are the same. | hep |
Possible influence of the two string events on the hadron formation in a
nuclear environment: One of the basic assumptions of the string model is that as a result of a DIS
in nucleus a single string arises, which then breaks into hadrons. However the
pomeron exchange considered in this work, leads to the production of two
strings in the one event. The hadrons produced in these events have smaller
formation lengths, than those with the same energy produced in the single
string events. As a consequence, they undergo more substantial absorption in
the nuclear matter. | hep |
Nearly Degenerate Neutrino Masses and Nearly Decoupled Neutrino
Oscillations: We introduce a simple flavor symmetry breaking scheme, in which charged
lepton masses have a strong hierarchy and neutrino masses are almost
degenerate. It is possible to obtain a natural suppression of lepton flavor
mixing between the 1st and 3rd families as well as the approximate decoupling
of atmospheric and solar neutrino oscillations with nearly bi-maximal mixing
factors. The similarity and difference between lepton and quark flavor mixing
schemes are briefly discussed. | hep |
Hairy black holes and holographic heat engine: By considering AdS charged black hole in the context of extended
thermodynamic as the working substance we use it as a heat engine. We
investigate the effect of hairy charge on the evolution of efficiency and
Carnot efficiency along with electric charge. Because of interesting
thermodynamic behavior of hairy black holes it would be natural to know their
effects when we use black hole as a heat engine. We show that the hairy charge
increases the efficiency, and so maximum temperature would be happened for
bigger Maxwell charge when this hairy charge grows. For the fixed electric
charges, the efficiency has a minimum value. In fact all critical points
describe physical states except when the charge removed. If the electric charge
takes a zero value then the hairy charge must be negative. We also seek
behavior of the system for large charges which is provided a model with
low-temperature thermodynamics. | hep |
Higgs Sector Motivations for an e-minus e-minus Linear Collider: I briefly review the crucial role an $\emem$ linear collider could play in
unravelling the nature of a non-minimal Higgs sector and/or
strongly-interacting $WW$ sector. | hep |
Interpreting LHCb's $Λ_b\to Λ_cτ\barν$ measurement and
puzzles in semileptonic $Λ_b$ decays: Normalizing the recent LHCb measurement of $\Lambda_b \to \Lambda_c \tau
\bar\nu$ to the standard model (SM) prediction for the $\Lambda_b \to \Lambda_c
\mu \bar\nu$ rate, instead of a LEP measurement, provides a more consistent
comparison with the SM prediction for the lepton flavor universality ratio
$R(\Lambda_c)$. This modestly increases $R(\Lambda_c)$ compared to the quoted
LHCb result, such that it no longer hints at a suppression compared to the SM,
which would be hard to accommodate in new physics scenarios that enhance
$R(D^{(*)})$. We point out that the fraction of excited states in inclusive
semileptonic $\Lambda_b$ decay may be significantly greater than the
corresponding fraction in $B$ decays. Possible implications are speculated
upon. | hep |
Discussions on the Line-shape of $X(4660)$ Resonance: A careful reanalysis is made on $e^+e^-\to X(4660)\to
(\Lambda_c\bar{\Lambda}_c)/(\psi'\pi\pi)$ processes, aiming at resolving the
apparent conflicts between Belle and BESIII data above
$\Lambda_c\bar{\Lambda}_c$ threshold. We use a model containing a Breit-Wigner
resonance and $\Lambda_c\bar{\Lambda}_c$ four-point contact interactions, with
which the enhancement right above the $\Lambda_c\bar{\Lambda}_c$ threshold is
well explained by a virtual pole generated by $\Lambda_c\bar{\Lambda}_c$
attractive final state interaction, located at $M_V=4.566\pm0.007$ GeV.
Meanwhile, $X(4660)$ remains to be a typical Breit-Wigner resonance, and is
hence of confinement nature. Our analysis strongly suggests the existence of
the virtual pole with statistical significance of $4.2$ standard deviation
($\sigma$). Nevertheless, the conclusion crucially depends on the line-shape of
cross sections which are of limited statistics, hence we urge new experimental
analyses from Belle II, BESIII, and LHCb to settle the issue. | hep |
Light Higgsinos, Heavy Gluino and $b-τ$ Quasi-Yukawa Unification:
Will the LHC find the Gluino?: A wide variety of unified models predict asymptotic relations at $M_{GUT}$
between the b quark and $\tau$ lepton Yukawa couplings. Within the framework of
supersymmetric SU(4) $\times$ SU(2)$_L \times$ SU(2)$_R$, we explore regions of
the parameter space that are compatible with b-$\tau$ quasi-Yukawa unification
and the higgsinos being the lightest supersymmetric particles ($\lesssim$ 1
TeV). Among the colored sparticles, the stop weighs more than 1.5 TeV or so,
whereas the squarks of the first two families are signifcantly heavier,
approaching 10 TeV in some cases. The gluino mass is estimated to lie in the
2-4 TeV range which raises the important question: Will the LHC find the
gluino? | hep |
DGP Specteroscopy: We systematically explore the spectrum of gravitational perturbations in
codimension-1 DGP braneworlds, and find a 4D ghost on the self-accelerating
branch of solutions. The ghost appears for any value of the brane tension,
although depending on the sign of the tension it is either the helicity-0
component of the lightest localized massive tensor of mass $0<m^2 < 2H^2$ for
positive tension, the scalar `radion' for negative tension, or their admixture
for vanishing tension. Because the ghost is gravitationally coupled to the
brane-localized matter, the self-accelerating solutions are not a reliable
benchmark for cosmic acceleration driven by gravity modified in the IR. In
contrast, the normal branch of solutions is ghost-free, and so these solutions
are perturbatively safe at large distance scales. We further find that when the
$\mathbb{Z}_2$ orbifold symmetry is broken, new tachyonic instabilities, which
are much milder than the ghosts, appear on the self-accelerating branch.
Finally, using exact gravitational shock waves we analyze what happens if we
relax boundary conditions at infinity. We find that non-normalizable bulk
modes, if interpreted as 4D phenomena, may open the door to new ghost-like
excitations. | hep |
Renormalization Theory for Interacting Crumpled Manifolds: We consider a continuous model of D-dimensional elastic (polymerized)
manifold fluctuating in d-dimensional Euclidean space, interacting with a
single impurity via an attractive or repulsive delta-potential (but without
self-avoidance interactions). Except for D=1 (the polymer case), this model
cannot be mapped onto a local field theory. We show that the use of intrinsic
distance geometry allows for a rigorous construction of the high-temperature
perturbative expansion and for analytic continuation in the manifold dimension
D. We study the renormalization properties of the model for 0<D<2, and show
that for d<d* where d*=2D/(2-D) is the upper critical dimension, the
perturbative expansion is UV finite, while UV divergences occur as poles at
d=d*. The standard proof of perturbative renormalizability for local field
theories (the BPH theorem) does not apply to this model. We prove perturbative
renormalizability to all orders by constructing a subtraction operator based on
a generalization of the Zimmermann forests formalism, and which makes the
theory finite at d=d*. This subtraction operation corresponds to a
renormalization of the coupling constant of the model (strength of the
interaction with the impurity). The existence of a Wilson function, of an
epsilon-expansion around the critical dimension, of scaling laws for d<d* in
the repulsive case, and of non-trivial critical exponents of the delocalization
transition for d>d* in the attractive case is thus established. To our
knowledge, this provides the first proof of renormalizability for a model of
extended objects, and should be applicable to the study of self-avoidance
interactions for random manifolds. | hep |
Generalized Gaugino Condensation in Super Yang-Mills Theories: Discrete
R-Symmetries and Vacua: One can define generalized models of gaugino condensation as theories which
dynamically break a discrete R-symmetry, but do not break supersymmetry. We
consider general examples consisting of gauge and matter fields, and the
minimal number of gauge singlet fields to avoid flat directions in the
potential. We explore which R-symmetries can arise, and their spontaneous
breaking. In general, we find that the discrete symmetry is
$\mathbb{Z}_{2b_0R}$ and the number of supersymmetric vacua is $b_0$, where
$b_0$ is the coefficient of the one-loop beta function. Results are presented
for various groups, including $SU(N_c), SO(N_c), Sp(2N_c)$, and $G_2$, for
various numbers of flavors, $N_f$, by several methods. This analysis can also
apply to the other exceptional groups, and thus all simple Lie groups. We also
comment on model building applications where a discrete R-symmetry, broken by
the singlet vevs, can account for $\mu$-type terms and allow a realistic Higgs
spectrum naturally. | hep |
An Extended Colored Zee-Babu Model: We study the extended colored Zee-Babu model introducing a vector-like quark
and singlet scalar. The active neutrino mass matrix and muon anomalous magnetic
moment are analyzed, which can be fitted to experimental data satisfying the
constraints from flavor changing neutral current. Then we discuss signature of
our model via vector-like quark production. In addition, the diphoton excess
can be explained with the contribution from vector-like quark | hep |
Dark Matter and Global Symmetries: General considerations in general relativity and quantum mechanics are known
to potentially rule out continuous global symmetries in the context of any
consistent theory of quantum gravity. Assuming the validity of such
considerations, we derive stringent bounds from gamma-ray, X-ray, cosmic-ray,
neutrino, and CMB data on models that invoke global symmetries to stabilize the
dark matter particle. We compute up-to-date, robust model-independent limits on
the dark matter lifetime for a variety of Planck-scale suppressed
dimension-five effective operators. We then specialize our analysis and apply
our bounds to specific models including the Two-Higgs-Doublet, Left-Right,
Singlet Fermionic, Zee-Babu, 3-3-1 and Radiative See-Saw models. {Assuming that
(i) global symmetries are broken at the Planck scale, that (ii) the
non-renormalizable operators mediating dark matter decay have $O(1)$ couplings,
that (iii) the dark matter is a singlet field, and that (iv) the dark matter
density distribution is well described by a NFW profile}, we are able to rule
out fermionic, vector, and scalar dark matter candidates across a broad mass
range (keV-TeV), including the WIMP regime. | hep |
Extended Lambda-Maxwell duality and related large class of dyonic and
neutral exactly solvable 4D Einstein-Maxwell-dilaton models discovered: We report the discovered class of exact static solutions of several 4D
Einstein-Maxwell-dilaton systems: string-induced, Liouville, trigonometric,
polynomial, etc., for three basic topologies (spherical, hyperbolical and flat)
being uniformly treated. In addition to the usual electric-magnetic duality
this class obeys a certain extended duality between Maxwell-dilaton coupling
and dilaton mass. Though major solutions we obtain are dyonic, the class also
comprises interesting neutral models.
As a by-product, we significantly succeded in resolving of the two important
problems, one of which has been standing more than a decade (system with the
string-inspired exponential Maxwell-dilaton coupling and non-vanishing dilaton
mass) and another one - gravity coupled to massive neutral scalar field:
generalized Liouville, Sin(h), Cos(h) - is about fifty years old.
Finally, we demonstrate the full separability of the static EMD system and
publicize the simple procedure of how to generate new integrability classes. | hep |
Aspects of Three-dimensional Spin-4 Gravity: We discuss some interesting holographical aspects of three-dimensional
higher-spin gravity with a negative cosmological constant in the framework of
SL(4, R) \times SL(4, R) Chern-Simons theory. Using a recently found technique,
we construct explicitly a solution that can be interpreted as spin-4
generalization of the BTZ solution, and demonstrate how W_4 symmetry and the
higher-spin Ward identities arise from the bulk equations of motion coupled to
spin-3 and spin-4 currents. We match the eigenvalues of a Wilson loop along the
time-like direction of the BTZ to that of the spin-4 solution, and show that
this yields remarkably consistent gravitational thermodynamics for the latter.
This furnishes an important, concrete supporting example for a recent proposal
to understand spacetime geometries in three-dimensional higher-spin gravity
formulated via SL(N, R) \times SL(N, R) Chern-Simons theories. | hep |
Predicting the $\sinφ_S$ Transverse Single-spin Asymmetry of Pion
Production at an Electron Ion Collider: We study the transverse single-spin asymmetry with a $\sin\phi_S$ modulation
in semi-inclusive deep inelastic scattering. Particularly, we consider the case
in which the transverse momentum of the final state hadron is integrated out.
Thus, the asymmetry is merely contributed by the coupling of the transversity
distribution function $h_1(x)$ and the twist-3 collinear fragmentation function
$\tilde{H}(z)$. Using the available parametrization of $h_1(x)$ from SIDIS data
and the recent extracted result for $\tilde{H}(z)$, we predict the $\sin\phi_S$
asymmetry for charged and neutral pion production at an Electron Ion Collider.
We find that the asymmetry is sizable and could be measured. We also study the
impact of the leading-order QCD evolution effect and find that it affects the
$\sin\phi_S$ asymmetry at EIC considerably. | hep |
The Skyrmion strikes back: baryons and a new large $N_c$ limit: In the large $N_c$ limit of QCD, baryons can be modeled as solitons, for
instance, as Skyrmions. This modeling has been justified by Witten's
demonstration that all properties of baryons and mesons scale with $N_c^{-1/2}$
in the same way as the analogous meson-based soliton model scales with a
generic meson-meson coupling constant $g$. An alternative large $N_c$ limit
(the orientifold large $N_c$ limit) has recently been proposed in which quarks
transform in the two-index antisymmetric representation of $SU(N_c)$. By
carrying out the analog of Witten's analysis for the new orientifold large
$N_c$ limit, we show that baryons and solitons can also be identified in the
orientifold large $N_c$ limit. However, in the orientifold large $N_c$ limit,
the interaction amplitudes and matrix elements scale with $N_c^{-1}$ in the
same way as soliton models scale with the generic meson coupling constant $g$
rather than as $N_c^{-1/2}$ as in the traditional large $N_c$ limit. | hep |
Radiative Two Loop Inverse Seesaw and Dark Matter: Seesaw mechanism provides a natural explanation of light neutrino masses
through suppression of heavy seesaw scale. In inverse seesaw models the seesaw
scale can be much lower than that in the usual seesaw models. If terms inducing
seesaw masses are further induced by loop corrections, the seesaw scale can be
lowered to be in the range probed by experiments at the LHC without fine
tuning. In this paper we construct models in which inverse seesaw neutrino
masses are generated at two loop level. These models also naturally have dark
matter candidates. Although the recent data from Xenon100 put stringent
constraint on the models, they can be consistent with data on neutrino masses,
mixing, dark matter relic density and direct detection. These models also have
some interesting experimental signatures for collider and flavor physics. | hep |
Spectral function of the Bloch-Nordsieck model at finite temperature: In this paper we determine the exact fermionic spectral function of the
Bloch-Nordsieck model at finite temperature. Analytic results are presented for
some special parameters, for other values we have numerical results. The
spectral function is finite and normalizable for any nonzero temperature
values. The real time dependence of the retarded Green's function is power-like
for small times and exhibits exponential damping for large times. Treating the
temperature as an infrared regulator, we can also give a safe interpretation of
the zero temperature result. | hep |
Predicting $\sin(2φ-φ_{s})$ azimuthal asymmetry in pion-proton
induced Drell-Yan process using holographic light-front QCD: We compute the $\sin(2\phi-\phi_{s})$ azimuthal asymmetry in the pion-nucleon
induced Drell-Yan process within transverse momentum dependent factorization.
We employ the holographic light-front pion wave functions to calculate its
leading-twist transverse momentum dependent parton distributions (TMDs). The
Boer-Mulders TMD of the pion is then convoluted with the transversity TMD of
the proton evaluated in a light-front quark-diquark model constructed with the
wave functions predicted by the soft-wall AdS/QCD to obtain the azimuthal
asymmetry in the Drell-Yan process. The gluon rescattering is pivotal to
predict nonzero pion Boer-Mulders TMD. We investigate the utility of a
nonperturbative SU$(3)$ gluon rescattering kernel going beyond the usual
approximation of perturbative U$(1)$ gluons. The holographic light-front QCD
approach provides a powerful tool for exploring the role of nonperturbative QCD
effects in the Drell-Yan process and may help to guide future experimental
measurements. | hep |
Calculating the Rest Tension for a Polymer of String Bits: We explore the application of approximation schemes from many body physics,
including the Hartree-Fock method and random phase approximation (RPA), to the
problem of analyzing the low energy excitations of a polymer chain made up of
bosonic string bits. We accordingly obtain an expression for the rest tension
$T_0$ of the bosonic relativistic string in terms of the parameters
characterizing the microscopic string bit dynamics. We first derive an exact
connection between the string tension and a certain correlation function of the
many-body string bit system. This connection is made for an arbitrary
interaction potential between string bits and relies on an exact dipole sum
rule. We then review an earlier calculation by Goldstone of the low energy
excitations of a polymer chain using RPA. We assess the accuracy of the RPA by
calculating the first order corrections. For this purpose we specialize to the
unique scale invariant potential, namely an attractive delta function potential
in two (transverse) dimensions. We find that the corrections are large, and
discuss a method for summing the large terms. The corrections to this improved
RPA are roughly 15\%. | hep |
S-wave nonleptonic hyperon decays and $Ξ^-_b \to π^- Λ_b$: The decay $\Xi^-_b \to \pi^- \Lambda_b$ has recently been observed by the
LHCb Collaboration at CERN. In contrast to most weak decays of $b$-flavored
baryons, this process involves the decay of the strange quark in $\Xi_b$, and
thus has features in common with nonleptonic weak decays of hyperons. Thanks to
the expected pure S-wave nature of the decay in question in the heavy $b$ quark
limit, we find that its amplitude may be related to those for S-wave
nonleptonic decays of $\Lambda$, $\Sigma$, and $\Xi$ in a picture inspired by
duality. The calculated branching fraction ${\cal B}(\Xi^-_b \to \pi^-
\Lambda_b) = (6.3 \pm 4.2) \times 10^{-3}$ is consistent with the range allowed
in the LHCb analysis. The error is dominated by an assumed 30\% uncertainty in
the amplitude due to possible U(3) violation. A more optimistic view based on
sum rules involving nonleptonic hyperon decay S-wave amplitudes reduces the
error on the branching fraction to $2.0 \times 10^{-3}$. | hep |
Neutrino masses, dark matter and leptogenesis with $U(1)_{B-L}$ gauge
symmetry: We propose a model with an $U(1)_{B-L}$ gauge symmetry, in which small
neutrino masses, dark matter and the matter-antimatter asymmetry in the
Universe can be simultaneously explained. In particular, the neutrino masses
are generated radiatively, while the matter-antimatter asymmetry is led by the
leptogenesis mechanism, at TeV scale. We also explore allowed regions of the
model parameters and discuss some phenomenological effects including lepton
flavor violating processes. | hep |
Lorentz Invariance, Scattering Amplitudes and the Emergence of
Semiclassical Geometry: It has been known for some time now that error correction plays a fundamental
role in the determining the emergence of semiclassical geometry in quantum
gravity. In this work I connect several different lines of reasoning to argue
that this should indeed be the case. The kinematic data which describes the
scattering of $ N $ massless particles in flat spacetime can put in one-to-one
correspondence with coherent states of quantum geometry. These states are
labeled by points in the Grassmannian $ Gr_{2,n} $, which can be viewed as
labeling the code-words of a quantum error correcting code. The condition of
Lorentz invariance of the background geometry can then be understood as the
requirement that co-ordinate transformations should leave the code subspace
unchanged. In this essay I show that the language of subsystem (or operator)
quantum error correcting codes provides the proper framework for understanding
these aspects of particle scattering and quantum geometry. | hep |
Deep generative models for fast photon shower simulation in ATLAS: The need for large-scale production of highly accurate simulated event
samples for the extensive physics programme of the ATLAS experiment at the
Large Hadron Collider motivates the development of new simulation techniques.
Building on the recent success of deep learning algorithms, variational
autoencoders and generative adversarial networks are investigated for modelling
the response of the central region of the ATLAS electromagnetic calorimeter to
photons of various energies. The properties of synthesised showers are compared
with showers from a full detector simulation using GEANT4. Both variational
autoencoders and generative adversarial networks are capable of quickly
simulating electromagnetic showers with correct total energies and
stochasticity, though the modelling of some shower shape distributions requires
more refinement. This feasibility study demonstrates the potential of using
such algorithms for ATLAS fast calorimeter simulation in the future and shows a
possible way to complement current simulation techniques. | hep |
On the nature of fermion-monopole supersymmetry: It is shown that the generator of the nonstandard fermion-monopole
supersymmetry uncovered by De Jonghe, Macfarlane, Peeters and van Holten, and
the generator of its standard N=1/2 supersymmetry have to be supplemented by
their product operator to be treated as independent supercharge. As a result,
the fermion-monopole system possesses the nonlinear N=3/2 supersymmetry having
the nature of the 3D spin-1/2 free particle's supersymmetry generated by the
supercharges represented in a scalar form. Analyzing the supercharges'
structure, we trace how under reduction of the fermion-monopole system to the
spherical geometry the nonlinear N=3/2 superalgebra comprising the Hamiltonian
and the total angular momentum as even generators is transformed into the
standard linear N=1 superalgebra with the Hamiltonian to be the unique even
generator. | hep |
Noncommutative corrections to the minimal surface areas of the pure AdS
spacetime and Schwarzschild-AdS black hole: Based on the perturbation expansion, we compute the noncommutative
corrections to the minimal surface areas of the pure AdS spacetime and
Schwarzschild-AdS black hole, where the noncommutative background is suitably
constructed in terms of the Poincar\'e coordinate system. In particular, we
find a reasonable tetrad with subtlety, which not only matches the metrics of
the pure AdS spacetime and Schwarzschild-AdS black hole in the commutative
case, but also makes the corrections real rather than complex in the
noncommutative case. For the pure AdS spacetime, the nocommutative effect is
only a logarithmic term, while for the Schwarzschild-AdS black hole, it
contains a logarithmic contribution plus both a mass term and a noncommutative
parameter related term. Furthermore, we show that the holographic entanglement
entropy with noncommutativity obeys a relation which is similar to the first
law of thermodynamics in the pure AdS spacetime. | hep |
Calculation of Green-Schwarz Superstring Amplitudes Using the N=2
Twistor-String Formalism: The manifestly SU(4)xU(1) super-Poincare invariant free-field N=2 twistor-
string action for the ten-dimensional Green-Schwarz superstring is quantized
using standard BRST methods. Unlike the light-cone and semi-light-cone
gauge-fixed Green-Schwarz actions, the twistor-string action does not require
interaction-point operators at the zeroes of the light-cone momentum, $\dz
x^+$, which complicated all previous calculations. After defining the vertex
operator for the massless physical supermultiplet, as well as two
picture-changing operators and an instanton-number-changing operator,
scattering amplitudes for an arbitrary number of loops and external massless
states are explicitly calculated by evaluating free-field correlation functions
of these operators on N=2 super-Riemann surfaces of the appropriate topology,
and integrating over the global moduli. Although there is no sum over spin
structures, only discrete values of the global U(1) moduli contribute to the
amplitudes. Because the spacetime supersymmetry generators do not contain ghost
fields, the amplitudes are manifestly spacetime supersymmetric, there is no
multiloop ambiguity, and the non-renormalization theorem is easily proven. By
choosing the picture-changing operators to be located at the zeroes of $\dz
x^+$, these amplitudes are shown to agree with amplitudes obtained using the
manifestly unitary light-cone gauge formalism. | hep |
BV QUANTIZATION OF A VECTOR-TENSOR GAUGE THEORY WITH TOPOLOGICAL
COUPLING: We use the BV quantization method for a theory with coupled tensor and vector
gauge fields through a topological term. We consider in details the
reducibility of the tensorial sector as well as the appearance of a mass term
in the effective vectorial theory . | hep |
Composite electric S-brane solutions with maximal number of branes and
several scalar fields: A (n+1)-dimensional cosmological model with a set of scalar fields and
antisymmetric (p+2)-form is considered. Some of scalar fields may have negative
kinetic terms, i.e. they may describe ``phantom'' fields. For certain odd
dimensions (D = 4m+1 = 5, 9, 13, ...) and (p+2)-forms (p = 2m-1 = 1, 3, 5, ...)
and non-exceptional dilatonic coupling vector $\vec{\lambda}$ we obtain
cosmological-type solutions to the field equations. These solutions are
characterized by self-dual or anti-self-dual charge density forms Q (of rank
2m) and may describe the maximal set of branes (i.e. when all the branes have
non-zero charge densities). Some properties of these solutions are considered,
e.g. Kasner-like behavior, the existence of non-singular (e.g. bouncing)
solutions and those with acceleration. The solutions with bouncing and
acceleration take place when at least there is one ``phantom'' field in the
model. | hep |
The Dynamical Composite Higgs: We present a simple microscopic realization of a pseudo-Nambu-Goldstone
(pNGB) boson Higgs scenario arising from the breaking of $SO(5) \rightarrow
SO(4)$. The Higgs constituents are explicitly identified as well as the
interactions responsible for forming the bound state and breaking the
electroweak symmetry. This outcome follows from the presence of four-fermion
interactions with a super-critical coupling, and uses the Nambu-Jona-Lasinio
mechanism to break the global $SO(5)$ symmetry. The Higgs potential is found to
be insensitive to high energy scales due to the existence of an approximate
infrared fixed point. The appearance of vector resonances is described and the
correspondence with other proposals in the literature established. The model
described here is significantly simpler than other recent ultraviolet
completions of pNGB scenarios. The observed Higgs mass can be accommodated, and
agreement with electroweak precision tests achieved in certain regions of
parameter space. There are also new vector-like fermions, some of which may lie
within reach of the LHC. In addition, we predict a heavy standard model singlet
scalar in the multi-TeV range. The amount of fine-tuning required in the model
is studied. Finally, we show that such a scheme can be completed in the
ultraviolet by a renormalizable theory. | hep |
JUNIPR: a Framework for Unsupervised Machine Learning in Particle
Physics: In applications of machine learning to particle physics, a persistent
challenge is how to go beyond discrimination to learn about the underlying
physics. To this end, a powerful tool would be a framework for unsupervised
learning, where the machine learns the intricate high-dimensional contours of
the data upon which it is trained, without reference to pre-established labels.
In order to approach such a complex task, an unsupervised network must be
structured intelligently, based on a qualitative understanding of the data. In
this paper, we scaffold the neural network's architecture around a
leading-order model of the physics underlying the data. In addition to making
unsupervised learning tractable, this design actually alleviates existing
tensions between performance and interpretability. We call the framework
JUNIPR: "Jets from UNsupervised Interpretable PRobabilistic models". In this
approach, the set of particle momenta composing a jet are clustered into a
binary tree that the neural network examines sequentially. Training is
unsupervised and unrestricted: the network could decide that the data bears
little correspondence to the chosen tree structure. However, when there is a
correspondence, the network's output along the tree has a direct physical
interpretation. JUNIPR models can perform discrimination tasks, through the
statistically optimal likelihood-ratio test, and they permit visualizations of
discrimination power at each branching in a jet's tree. Additionally, JUNIPR
models provide a probability distribution from which events can be drawn,
providing a data-driven Monte Carlo generator. As a third application, JUNIPR
models can reweight events from one (e.g. simulated) data set to agree with
distributions from another (e.g. experimental) data set. | hep |
Generalized Q-Exponentials Related to Orthogonal Quantum Groups and
Fourier Transformations of Noncommutative Spaces: An essential prerequisite for the study of q-deformed physics are particle
states in position and momentum representation. In order to relate x- and
p-space by Fourier transformations the appropriate q-exponential series related
to orthogonal quantum symmetries is constructed. It turns out to be a new
q-special function giving rise to q-plane wave solutions that transform with a
noncommuting phase under translations. | hep |
Gauge- and point-invariant vertices of nucleon-to-resonance interactions: We construct interactions of nucleons N with higher-spin resonances R
invariant under point and gauge transformations of the Rarita-Schwinger field.
It is found for arbitrarily high spin of a resonance that the requirement of
point- and gauge-invariance uniquely determines a Lagrangian of NR interactions
with pions, photons, and vector mesons, which might reduce model ambiguity in
effective-field calculations involving such vertices. Considering the NR
interactions with photons and vector mesons, the symmetry provides a
classification of three NR vertices in terms of their differential order. The
Q^2 dependencies of the point and gauge invariant form factors are considered
in a vector-meson-dominance model. The model is in good agreement with
experimental data. In addition, we point out some empirical patterns in the Q^2
dependencies of the form factors: low-Q^2 scaling of the N-Delta(1232) form
factor ratios and relations between form factors for N-N(1520) and N-N(1680)
transitions. | hep |
Cosmological Constraints on Large Extra Dimensions: We calculate the production of massive Kaluza-Klein(KK) modes via
nucleon-nucleon gravi-bremsstrahlung in the early universe. Overproduction of
these states would result in early matter domination and therefore a low age
for the universe so it is possible to place constraints on the number and size
of large extra dimensions. The constraints are stronger than those from Sn1987a
- for 2 large extra dimensions and T_QCD=170 MeV, we show the fundamental scale
must be larger than 1,000 TeV. | hep |
Zero mode-soliton duality and pKdV kinks in Boussinesq system for
non-linear shallow water waves: A Boussinesq system for a non-linear shallow water is considered. The
nonlinear and topological effects are examined through an associated matrix
spectral problem. It is shown an equivalence relationship between the bound
states and topological soliton charge densities which resembles a formula of
the Atiyah-Patodi-Singer-type index theorem. The zero mode components describe
a topologically protected Kelvin wave of KdV-type and a novel Boussinesq-type
field. We show that either the $1+1$ dimensional pKdV kink or the Kelvin mode
can be mapped to the bulk velocity potential in $2+1$ dimensions. | hep |
Scale Anomalies, States, and Rates in Conformal Field Theory: This paper presents two methods to compute scale anomaly coefficients in
conformal field theories (CFTs), such as the c anomaly in four dimensions, in
terms of the CFT data. We first use Euclidean position space to show that the
anomaly coefficient of a four-point function can be computed in the form of an
operator product expansion (OPE), namely a weighted sum of OPE coefficients
squared. We compute the weights for scale anomalies associated with scalar
operators and show that they are not positive. We then derive a different sum
rule of the same form in Minkowski momentum space where the weights are
positive. The positivity arises because the scale anomaly is the coefficient of
a logarithm in the momentum space four-point function. This logarithm also
determines the dispersive part, which is a positive sum over states by the
optical theorem. The momentum space sum rule may be invalidated by UV and/or IR
divergences, and we discuss the conditions under which these singularities are
absent. We present a detailed discussion of the formalism required to compute
the weights directly in Minkowski momentum space. A number of explicit checks
are performed, including a complete example in an 8-dimensional free field
theory. | hep |
Heavy quark induced effective action for gauge fields in the SU(N_c) x
U(1) model and the low-energy structure of heavy quark current correlators: We calculate the low-energy limit of heavy quark current correlators within
an expansion in the inverse heavy quark mass. The induced low-energy currents
built from the gluon fields corresponding to the initial heavy quark currents
are obtained from an effective action for gauge fields in the one-loop
approximation at the leading order of the 1/m expansion. Explicit formulae for
the low-energy spectra of electromagnetic and tensor heavy quark current
correlators are given. Consequences of the appearance of a nonvanishing
spectral density below the two-particle threshold for high precision
phenomenology of heavy quarks are discussed quantitatively. | hep |
$σ$ exchange in the one-boson exchange model involving the ground
state octet baryons: Based on the one-boson-exchange framework that the $\sigma$ meson serves as
an effective parameterization for the correlated scalar-isoscalar $\pi\pi$
interaction, we calculate the coupling constants of the $\sigma$ to the
$\frac{1}{2}^+$ ground state light baryon octet ${\mathbb B}$ by matching the
amplitude of ${\mathbb B}\bar{{\mathbb B}}\to\pi\pi\to\bar{{\mathbb B}}{\mathbb
B}$ to that of ${\mathbb B}\bar{{\mathbb B}}\to\sigma\to\bar{{\mathbb
B}}{\mathbb B}$. The former is calculated using a dispersion relation,
supplemented with chiral perturbation theory results for the ${\mathbb
B}{\mathbb B}\pi\pi$ couplings and the Muskhelishvili-Omn\` es representation
for the $\pi\pi$ rescattering. Explicitly, the coupling constants are obtained
as $g_{NN\sigma}=8.7_{-1.9}^{+1.7}$,
$g_{\Sigma\Sigma\sigma}=3.5_{-1.3}^{+1.8}$,
$g_{\Xi\Xi\sigma}=2.5_{-1.4}^{+1.5}$, and
$g_{\Lambda\Lambda\sigma}=6.8_{-1.7}^{+1.5}$. These coupling constants can be
used in the one-boson-exchange model calculations of the interaction of light
baryons with other hadrons. | hep |
Slow Roll during the Waterfall Regime: The Small Coupling Window for
SUSY Hybrid Inflation: It has recently been pointed out that a substantial amount of e-folds can
occur during the waterfall regime of hybrid inflation. Moreover, Kodama et.al.
have derived analytic approximations for the trajectories of the inflaton and
of the waterfall fields. Based on these, we derive here the consequences for F-
and D-term SUSY hybrid inflation: A substantial amount of e-folds may occur in
the waterfall regime, provided kappa << M^2/M_P^2, where kappa is the
superpotential coupling, M the scale of symmetry breaking and M_P the reduced
Planck mass. When this condition is amply fulfilled, a number of e-folds much
larger than N_e\approx60 can occur in the waterfall regime and the scalar
spectral index is then given by the expression found by Kodama et.al.
n_s=1-4/N_e. This value may be increased up to unity, if only about N_e e-folds
occur during the waterfall regime, such that the largest observable scale
leaves the horizon close to the critical point of hybrid inflation, what can be
achieved for kappa\approx10^(-13) and M\approx5x10^(12) GeV in F-term
inflation. Imposing the normalization of the power spectrum leads to a lower
bound on the scale of symmetry breaking. | hep |
Lorentzian quantum gravity and the graviton spectral function: We present the first direct and non-perturbative computation of the graviton
spectral function in quantum gravity. This is achieved with the help of a novel
Lorentzian renormalisation group approach, combined with a spectral
representation of correlation functions. We find a positive graviton spectral
function, showing a massless one-graviton peak and a multi-graviton continuum
with an asymptotically safe scaling for large spectral values. We also study
the impact of a cosmological constant. Further steps to investigate scattering
processes and unitarity in asymptotically safe quantum gravity are indicated. | hep |
A Double Take on New Physics in Double Higgs Production: Gluon-initiated double Higgs production is the most important channel to
extract the Higgs self-coupling at hadron colliders. However, new physics could
enter into this channel in several distinctive ways including, but not limited
to, the Higgs self-coupling, a modified top Yukawa coupling, and an anomalous
Higgs-top quartic coupling. In this work we initiate a study on the interplay
of these effects in the kinematic distributions of the Higgs bosons. More
specifically, we divide the transverse momentum and the total invariant mass
spectra into two bins and use the differential rates in each bin to constrain
the magnitude of the aforementioned effects. Significantly improved results
could be obtained over those using total cross section alone. However, some
degeneracy remains, especially in the determination of the Higgs trilinear
coupling. Therefore, an accurate measurement of the Higgs self-coupling in this
channel would require precise knowledge of the magnitudes of other new physics
effects. We base our analysis on a future 100 TeV proton-proton collider. | hep |
Classification of lepton mixing patterns from finite flavour symmetries: Flavour symmetries have been used to constrain both quark and lepton mixing
parameters. In particular, they can be used to completely fix the mixing
angles. For the lepton sector, assuming that neutrinos are Majorana particles,
we have derived the complete list of mixing patterns achievable in this way, as
well as the symmetry groups associated to each case. Partial computer scans
done in the past have hinted that such list is limited, and this does indeed
turn out to be the case. In addition, most mixing patterns are already 3-sigma
excluded by neutrino oscillation data. | hep |
Search for neutrino non-standard interactions with ANTARES and
KM3NeT-ORCA: Non-standard interactions (NSIs) in the propagation of neutrinos in matter
can lead to significant deviations in neutrino oscillations expected within the
standard 3-neutrino framework. These additional interactions would result in an
anomalous flux of neutrinos observable at neutrino telescopes. The ANTARES
detector and its next-generation successor, KM3NeT, located in the abyss of the
Mediterranean Sea, have the potential to measure sub-dominant effects in
neutrino oscillations, coming from non-standard neutrino interactions. In this
contribution, a likelihood-based search for NSIs with 10 years of atmospheric
muon-neutrino data recorded with ANTARES is reported and sensitivity
projections for KM3NeT/ORCA, based on realistic detector simulations, are
shown. The bounds obtained with ANTARES in the NSI $\mu - \tau$ sector
constitute the most stringent limits up to date. | hep |
On Gauge Invariant Cosmological Perturbations in UV-modified Horava
Gravity: We consider gauge invariant cosmological perturbations in UV-modified, z=3
Horava gravity with one scalar matter field, which has been proposed as a
renormalizable gravity theory without the ghost problem in four dimensions. In
order to exhibit its dynamical degrees of freedom, we consider the Hamiltonian
reduction method and find that, by solving "all" the constraint equations, the
degrees of freedom are the same as those of Einstein gravity: One scalar and
two tensor (graviton) modes when a scalar matter field presents. However, we
confirm that there is no extra graviton modes and general relativity is
recovered in IR, which achieves the consistency of the model. From the
UV-modification terms which break the detailed balance condition in UV, we
obtain scale-invariant power spectrums for "non"-inflationary backgrounds, like
the power-law expansions, without knowing the details of early expansion
history of Universe. This could provide a new framework for the Big Bang
cosmology. Moreover, we find that "tensor and scalar fluctuations travel
differently in UV, generally". We present also some clarifying remarks about
confusing points in the literatures. | hep |
Displaced or invisible? ALPs from $B$ decays at Belle II: At colliders, neutral long-lived particles can be detected through displaced
decay products or as missing energy. Which search strategy is better depends on
the particle's decay length just as on the detector properties. We investigate
the complementarity of displaced and invisible signatures for the Belle II
experiment. Focusing on axion-like particles $a$ produced from meson decays, we
present a new search strategy for two-body decays $B^+ \to K^+ a, a\to
E\!\!\!/$ with missing energy $E\!\!\!/$. With $50\,$ab$^{-1}$ of data, Belle
II can probe light invisible resonances with branching ratio
$\mathcal{B}(B^+\to K^+ a) \gtrsim 10^{-7}$ and decay length $c\tau_a \gtrsim
1\,$m. For axion-like particles, we expect the sensitivity of $B^+ \to K^+
E\!\!\!/$ to small couplings to improve by up to two orders of magnitude
compared to previous searches at collider and fixed-target experiments. For
sub-GeV particles, $B^+ \to K^+ E\!\!\!/$ at Belle II and searches at beam-dump
experiments are most sensitive; for heavier particles, searches for displaced
vertices at Belle II, long-lived particle experiments at the LHC, and future
fixed-target experiments can probe the smallest couplings. | hep |
Energy Spectrum of Anyons in a Magnetic Field: For the many-anyon system in external magnetic field, we derive the energy
spectrum as an exact solution of the quantum eigenvalue problem with particular
topological constraints. Our results agree with the numerical spectra recently
obtained for the 3- and the 4-anyon systems. | hep |
Mirror Symmetry, D-brane Superpotential and Ooguri-Vafa Invariants of
Compact Calabi-Yau Manifolds: The D-brane superpotential is very important in the low energy effective
theory. As the generating function of all disk instantons from the worldsheet
point of view, it plays a crucial role in deriving some important properties of
the compact Calabi-Yau manifolds. By using the GKZ-generalized hypergeometric
system, we will calculate the B-brane superpotentials of two non-fermat type
compact Calabi-Yau hypersurfaces in toric varieties,respectively. Then
according to the mirror symmetry, we obtain the A-model superpotentials and the
Ooguri-Vafa invariants for the mirror Calabi-Yau manifolds. | hep |
Probing Transverse Momentum Broadening via Dihadron and Hadron-jet
Angular Correlations in Relativistic Heavy-ion Collisions: Dijet, dihadron, hadron-jet angular correlations have been reckoned as
important probes of the transverse momentum broadening effects in relativistic
nuclear collisions. When a pair of high-energy jets created in hard collisions
traverse the quark-gluon plasma produced in heavy-ion collisions, they become
de-correlated due to the vacuum soft gluon radiation associated with the
Sudakov logarithms and the medium-induced transverse momentum broadening. For
the first time, we employ the systematical resummation formalism and establish
a baseline calculation to describe the dihadron and hadron-jet angular
correlation data in $pp$ and peripheral $AA$ collisions where the medium effect
is negligible. We demonstrate that the medium-induced broadening $\langle
p_\perp^2\rangle$ and the so-called jet quenching parameter $\hat q$ can be
extracted from the angular de-correlations observed in $AA$ collisions. A
global $\chi^2$ analysis of dihadron and hadron-jet angular correlation data
renders the best fit $\langle p_\perp^2 \rangle \sim 13~\textrm{GeV}^2$ for a
quark jet at RHIC top energy. Further experimental and theoretical efforts
along the direction of this work shall significantly advance the quantitative
understanding of transverse momentum broadening and help us acquire
unprecedented knowledge of jet quenching parameter in relativistic heavy-ion
collisions. | hep |
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