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Symmetries, Spin-2 Scattering Amplitudes, and Equivalence theorems in
Warped Five-Dimensional Gravitational Theories: Building on work by Hang and He, we show how the residual five-dimensional
diffeomorphism symmetries of compactified gravitational theories with a warped
extra dimension imply Equivalence theorems which ensure that the scattering
amplitudes of helicity-0 and helicity-1 spin-2 Kaluza-Klein states equal (to
leading order in scattering energy) those of the corresponding Goldstone bosons
present in the `t-Hooft-Feynman gauge. We derive a set of Ward identities that
lead to a transparent power-counting of the scattering amplitudes involving
spin-2 Kaluza-Klein states. We explicitly calculate these amplitudes in terms
of the Goldstone bosons in the Randall-Sundrum model, check the correspondence
to previous unitary-gauge computations, and demonstrate the efficacy of
`t-Hooft-Feynman gauge for accurately computing amplitudes for scattering of
the spin-2 states both among themselves and with matter. Power-counting for the
Goldstone boson interactions establishes that the scattering amplitudes grow no
faster than $O(s)$, explaining the origin of the behavior previously shown to
arise from intricate cancellations between different contributions to these
scattering amplitudes in unitary gauge. We describe how our results apply to
more general warped geometries, including models with a stabilized extra
dimension. In an appendix we explicitly identify the symmetry algebra of the
residual 5D diffeomorphisms of a Randall-Sundrum extra-dimensional theory. | hep |
The Nucleon Electric Dipole Moment in Light-Front QCD: I present an exact relationship between the electric dipole moment and
anomalous magnetic moment of the nucleon in the light-front formalism of QCD
and consider its consequences. | hep |
Supersymmetric Proton Decay Revisited: Encouraged by the advent of a new generation of underground detectors---JUNO,
DUNE and Hyper-Kamiokande---that are projected to improve significantly on the
present sensitivities to various baryon decay modes, we revisit baryon decay in
the minimal supersymmetric SU(5) GUT. We discuss the phenomenological
uncertainties associated with hadronic matrix elements and the value of the
strong coupling $\alpha_s$---which are the most important---the weak mixing
angle $\theta_W$, quark masses including one-loop renormalization effects,
quark mixing and novel GUT phases that are not visible in electroweak
interaction processes. We apply our analysis to a variety of CMSSM, super- and
sub-GUT scenarios in which soft supersymmetry-breaking parameters are assumed
to be universal at, above and below the GUT scale, respectively. In many cases,
we find that the next generation of underground detectors should be able to
probe models with sparticle masses that are ${\cal O}(10)$~TeV, beyond the
reach of the LHC. | hep |
A closed clockwork theory: $\mathbb{Z}_2$ parity and more: We develop a new class of clockwork theories with an augmented structure of
the near-neighbour interactions along a one-dimensional closed chain. Such a
topology leads to new and attractive features in addition to generating light
states with hierarchical couplings via the usual clockwork mechanism. For one,
there emerges a $\mathbb{Z}_2$ symmetry under the exchange of fields resulting
in a physical spectrum consisting of states, respectively even and odd under
the exchange parity with a two-fold degeneracy at each level. The lightest odd
particle, being absolutely stable, could be envisaged as a potential dark
matter candidate. The theory can also be obtained as a deconstruction of a
five-dimensional theory embedded in a geometry generated by a linear dilaton
theory on a $S^1/\mathbb{Z}_2$ orbifold with three equidistant 3-branes.
Analogous to the discrete picture, the $\mathbb{Z}_2$ symmetry in the bulk
theory necessitates the existence of a KK spectrum of even and odd states, with
doubly degenerate modes at each KK level when subject to certain boundary
conditions. | hep |
High precision study of K+- --> 3pi+- decays by NA48/2: Preliminary results of study of $K^\pm\to3\pi^\pm$ decays by the NA48/2
experiment at CERN SPS are presented. They include a precise measurement of the
direct CP violating charge asymmetry of Dalitz plot linear slope parameters
$A_g=(g^+-g^-)/(g^++g^-)$, and a measurement of the Dalitz plot slope
parameters $(g,h,k)$ themselves. Due to the design of the experiment, and a
large data set collected, unprecedented precisions were achieved. | hep |
Dark energy from approximate U(1)_{de} symmetry: The PLANCK observation strengthens the argument that the observed
acceleration of the Universe is dominated by the invisible component of dark
energy. We address how this extremely small DE density can be obtained in an
ultraviolet completed theory. From two mass scales, the grand unification scale
M_G and the Higgs boson mass, we parametrize this dark energy(DE). To naturally
generate an extremely small DE term, we introduce an almost flat DE potential
of a pseudo-Goldstone boson of an approximate global symmetry U(1)_{de} from
some discrete symmetries allowed in an ultraviolet completed theory. For the DE
potential to be extremely shallow, the pseudo-Goldstone boson is required not
to couple to the QCD anomaly. This fixes uniquely the nonrenormalizable term
generating the potential suppressed by M_G^7 in supergravity models. | hep |
SUSY Long-Lived Massive Particles: Detection and Physics at the LHC: We draw a possible scenario for the observation of massive long-lived charged
particles at the LHC detector ATLAS. The required flexibility of the detector
triggers and of the identification and reconstruction systems are discussed. As
an example, we focus on the measurement of the mass and lifetime of long-lived
charged sleptons predicted in the framework of supersymmetric models with
gauge-mediated supersymmetry (SUSY) breaking. In this case, the
next-to-lightest SUSY particle can be the light scalar partner of the tau
lepton, possibly decaying slowly into a gravitino. A wide region of the SUSY
parameters space was explored. The accessible range and precision on the
measurement of the SUSY breaking scale parameter sqrt(F) achievable with a
counting method are assessed. | hep |
Finite Width in out-of-Equilibrium Propagators and Kinetic Theory: We derive solutions to the Schwinger-Dyson equations on the Closed-Time-Path
for a scalar field in the limit where backreaction is neglected. In Wigner
space, the two-point Wightman functions have the curious property that the
equilibrium component has a finite width, while the out-of equilibrium
component has zero width. This feature is confirmed in a numerical simulation
for scalar field theory with quartic interactions. When substituting these
solutions into the collision term, we observe that an expansion including terms
of all orders in gradients leads to an effective finite-width. Besides, we
observe no breakdown of perturbation theory, that is sometimes associated with
pinch singularities. The effective width is identical with the width of the
equilibrium component. Therefore, reconciliation between the zero-width
behaviour and the usual notion in kinetic theory, that the out-of-equilibrium
contributions have a finite width as well, is achieved. This result may also be
viewed as a generalisation of the fluctuation-dissipation relation to
out-of-equilibrium systems with negligible backreaction. | hep |
The N-Quantum Approximation and Bound States in Motion: We use an alternative method to the Bethe-Salpeter equation, the N-Quantum
approximation (NQA), for studying bound states in motion. We use this method to
find a relativistic equation for weakly bound states of two constituents with
different masses. We present rules for interpreting simple diagrams associated
with the NQA. We can use these rules to construct the bound state equations
directly, avoiding some of the complications of the process. The final result
is a bound state equation that shows Lorentz contraction in the direction of
motion explicitly. This result matches that of [3] found using the
Bethe-Salpeter equation. We briefly discuss some other applications of the NQA
in studying the effects of motion on bound states. | hep |
Path Integral Quantization of Cosmological Perturbations: We derive the first order canonical formulation of cosmological perturbation
theory in a Universe filled by a few scalar fields. This theory is quantized
via well-defined Hamiltonian path integral. The propagator which describes the
evolution of the initial (for instance, vacuum) state, is calculated. | hep |
Entanglement entropy and nonabelian gauge symmetry: Entanglement entropy has proven to be an extremely useful concept in quantum
field theory. Gauge theories are of particular interest, but for these systems
the entanglement entropy is not clearly defined because the physical Hilbert
space does not factor as a tensor product according to regions of space. Here
we review a definition of entanglement entropy that applies to abelian and
nonabelian lattice gauge theories. This entanglement entropy is obtained by
embedding the physical Hilbert space into a product of Hilbert spaces
associated to regions with boundary. The latter Hilbert spaces include degrees
of freedom on the entangling surface that transform like surface charges under
the gauge symmetry. These degrees of freedom are shown to contribute to the
entanglement entropy, and the form of this contribution is determined by the
gauge symmetry. We test our definition using the example of two-dimensional
Yang-Mills theory, and find that it agrees with the thermal entropy in de
Sitter space, and with the results of the Euclidean replica trick. We discuss
the possible implications of this result for more complicated gauge theories,
including quantum gravity. | hep |
Rigorous treatment of the $\mathcal{S}^1 / \mathbb{Z}_2$ orbifold model
with brane-Higgs couplings: We build rigorously the attractive five-dimensional model where bulk fermions
propagate along the $ \mathcal{S}^1 / \mathbb{Z}_2$ orbifold and interact with
a Higgs boson localised at a fixed point of the extra dimension. The analytical
calculation of the fermion mass spectrum and effective Yukawa couplings is
shown to require the introduction of either Essential Boundary Conditions (EBC)
imposed by the model definition or certain Bilinear Brane Terms (BBT) in the
action, instead of the usual brane-Higgs regularisations. The obtained fermion
profiles along the extra dimension turn out to undergo some discontinuities, in
particular at the Higgs brane, which can be mathematically consistent if the
action is well written with improper integrals. We also show that the
$\mathbb{Z}_2$ parity transformations in the bulk do not affect the fermion
chiralities, masses and couplings, in contrast with the EBC and BBT, but when
extended to the fixed points, they can generate the chiral nature of the theory
and even select the Standard Model chirality set-up while fixing as well the
fermion masses and couplings. Thanks to the strict analysis developed, the
duality with the interval model is scrutinised. | hep |
From Twistor Actions to MHV Diagrams: We show that MHV diagrams are the Feynman diagrams of certain twistor actions
for gauge theories in an axial gauge. The gauge symmetry of the twistor action
is larger than that on space-time and this allows us to fix a gauge that makes
the MHV formalism manifest but which is inaccessible from space-time. The
framework is extended to describe matter fields: as an illustration we
explicitly construct twistor actions for an adjoint scalar with arbitrary
polynomial potential and a fermion in the fundamental representation and show
how this leads to additional towers of MHV vertices in the MHV diagram
formalism. | hep |
Wigner functions of essentially nonequilibrium systems: The aim of the article is to discuss the S-matrix interpretation of
perturbation theory for the Wigner functions generating functional at a finite
temperature. For sake of definiteness, fruitful from pedagogical point of view,
the concrete problem from particle physics of high-temperature initial states
dissipation into cold one is considered from experimental and theoretical
points of view. The temperature is introduced in the theory by typical for the
microcanonical description way. The perturbation theory contains two-
temperature (of initial and final states) Green functions. Two possible
boundary conditions are considered. One of them is usual in a field theory
vacuum boundary condition. Corresponding generating functional of Wigner
functions can be used in the particle physics. Another type of the boundary
condition assumes that the system under consideration is in environment of the
black-body radiation. This leads to the usual in statistics
Kubo-Martin-Schwinger boundary condition at the equilibrium (one-temperature)
limit. The comparison of the S-matrix approach with Schwinger-Keldysh real-time
finite-temperature field theory and with nonstationary statistical operator
approach of Zubarev are considered. The range of applicability of the
finite-temperature description of dissipation processes is shown. | hep |
Cascading to the MSSM: The MSSM can arise as an orientifold of a pyramid-like quiver in the context
of intersecting D-branes. Here we consider quiver realizations of the MSSM
which can emerge at the bottom of a duality cascade. We classify all possible
minimal ways this can be done by allowing only one extra node. It turns out
that this requires extending the geometry of the pyramid to an octahedron. The
MSSM at the bottom of the cascade arises in one of two possible ways, with the
extra node disappearing either via Higgsing or confinement. Remarkably, the
quiver of the Higgsing scenario turns out to be nothing but the quiver version
of the left-right symmetric extension of the MSSM. In the minimal confining
scenario the duality cascade can proceed if and only if there is exactly one
up/down Higgs pair. Moreover, the symmetries of the octahedron naturally admit
an automorphism of the quiver which solves a version of the mu problem
precisely when there are an odd number of generations. | hep |
Divergent energy strings in $AdS_5\times S^5$ with three angular momenta: In this paper, novel solutions for strings with three angular momenta in
$AdS_5 \times S^5$ geometry are presented; the divergent energy limit and the
corresponding conserved charges, as well as dispersion relation are also
determined. Interpretations of these configurations as either a giant magnon
(GM) or a spiky string (SS) are discussed. | hep |
Hybrid Goldstone Modes from the Double Copy Bootstrap: We perform a systematic classification of scalar field theories whose
amplitudes admit a double copy formulation and identify two building blocks at
4-point and 13 at 5-point. Using the 4-point blocks as bootstrap seeds, this
naturally leads to a single copy theory that is a gauged NLSM. Moreover, its
double copy includes a novel theory that can be written in terms of Lovelock
invariants of an induced metric, and includes Dirac-Born-Infeld and the special
Galileon in specific limits. The amplitudes of these Goldstone modes have two
distinct soft behaviour regimes, corresponding to a hybrid of non-linear
symmetries. | hep |
Strange nucleon form factors in the perturbative chiral quark model: We apply the perturbative chiral quark model at one loop to calculate the
strange form factors of the nucleon. A detailed numerical analysis of the
strange magnetic moments and radii of the nucleon, and also the momentum
dependence of the form factors is presented. | hep |
The photon polarization tensor in pulsed Hermite- and Laguerre-Gaussian
beams: In this article, we provide analytical expressions for the photon
polarization tensor in pulsed Hermite- and Laguerre-Gaussian laser beams. Our
results are based on a locally constant field approximation of the one-loop
Heisenberg-Euler effective Lagrangian for quantum electrodynamics. Hence, by
construction they are limited to slowly varying electromagnetic fields, varying
on spatial and temporal scales significantly larger than the Compton
wavelength/time of the electron. The latter criterion is fulfilled by all laser
beams currently available in the laboratory. Our findings will, e.g., be
relevant for the study of vacuum birefringence experienced by probe photons
brought into collision with a high-intensity laser pulse which can be
represented as a superposition of either Hermite- or Laguerre-Gaussian modes. | hep |
Current-driven tricritical point in large-$N_{c}$ gauge theory: We discover a new tricritical point realized only in non-equilibrium steady
states, using the AdS/CFT correspondence. Our system is a (3+1)-dimensional
strongly-coupled large-$N_{c}$ gauge theory. The tricritical point is
associated with a chiral symmetry breaking under the presence of an electric
current and a magnetic field. The critical exponents agree with those of the
Landau theory of equilibrium phase transitions. This suggests that the presence
of a Landau-like phenomenological theory behind our non-equilibrium phase
transitions. | hep |
A non-perturbative exploration of the high energy regime in
$N_\text{f}=3$ QCD: Using continuum extrapolated lattice data we trace a family of running
couplings in three-flavour QCD over a large range of scales from about 4 to 128
GeV. The scale is set by the finite space time volume so that recursive finite
size techniques can be applied, and Schr\"odinger functional (SF) boundary
conditions enable direct simulations in the chiral limit. Compared to earlier
studies we have improved on both statistical and systematic errors. Using the
SF coupling to implicitly define a reference scale $1/L_0\approx 4$ GeV through
$\bar{g}^2(L_0) =2.012$, we quote $L_0 \Lambda^{N_{\rm f}=3}_{\overline{\rm
MS}} =0.0791(21)$. This error is dominated by statistics; in particular, the
remnant perturbative uncertainty is negligible and very well controlled, by
connecting to infinite renormalization scale from different scales $2^n/L_0$
for $n=0,1,\ldots,5$. An intermediate step in this connection may involve any
member of a one-parameter family of SF couplings. This provides an excellent
opportunity for tests of perturbation theory some of which have been published
in a letter [1]. The results indicate that for our target precision of 3 per
cent in $L_0 \Lambda^{N_{\rm f}=3}_{\overline{\rm MS}}$, a reliable estimate of
the truncation error requires non-perturbative data for a sufficiently large
range of values of $\alpha_s=\bar{g}^2/(4\pi)$. In the present work we reach
this precision by studying scales that vary by a factor $2^5= 32$, reaching
down to $\alpha_s\approx 0.1$. We here provide the details of our analysis and
an extended discussion. | hep |
Extraction of the Ratio of the Neutron to Proton Structure Functions
from Deep Inelastic Scattering: We study the nuclear ($A$) dependence of the European Muon Collaboration
(EMC) effect at high values of $x$ ($x \geq 0.6$). Our approach makes use of
conventional nuclear degrees of freedom within the Relativistic Impulse
Approximation. By performing a non-relativistic series expansion we demonstrate
that relativistic corrections make a substantial contribution to the effect at
$x \gtrsim 0.6$ and show that the ratio of neutron to proton structure
functions extracted from a global fit to all nuclei is not inconsistent with
values obtained from the deuteron. | hep |
Difficulties in a Kind of Averaging Procedure for Constructing
Gauge-invariant Operators out of Gauge-variant Ones: We prove that a kind of averaging procedure for constructing gauge-invariant
operators(or functionals) out of gauge-variant ones is erroneous and
inapplicable for a large class of operators(or functionals). | hep |
Kazhdan-Lusztig equivalence and fusion of Kac modules in Virasoro
logarithmic models: The subject of our study is the Kazhdan-Lusztig (KL) equivalence in the
context of a one-parameter family of logarithmic CFTs based on Virasoro
symmetry with the (1,p) central charge. All finite-dimensional indecomposable
modules of the KL-dual quantum group - the "full" Lusztig quantum sl(2) at the
root of unity - are explicitly described. These are exhausted by projective
modules and four series of modules that have a functorial correspondence with
any quotient or a submodule of Feigin-Fuchs modules over the Virasoro algebra.
Our main result includes calculation of tensor products of any pair of the
indecomposable modules. Based on the Kazhdan-Lusztig equivalence between
quantum groups and vertex-operator algebras, fusion rules of Kac modules over
the Virasoro algebra in the (1,p) LCFT models are conjectured. | hep |
Threshold effects and radiative electroweak symmetry breaking in $SU(5)$
extensions of the MSSM: We make a complete analysis of radiative symmetry breaking in the MSSM and
its $SU(5)$ extensions including low- and high-energy threshold effects in the
framework of the two-loop renormalization group. In particular, we consider
minimal $SU(5)$, the ``missing-doublet'' $SU(5)$, a Peccei-Quinn invariant
version of $SU(5)$ as well as a version with light adjoint remnants. We derive
permitted ranges for the parameters of these models in relation to predicted
$\alpha_{s}$ and $M_G$ values within the present experimental accuracy. The
parameter regions allowed under the constraints of radiative symmetry breaking,
perturbativity and proton stability, include the experimentally designated
domain for $\alpha_s$. In the case of the minimal $SU(5)$, the values of
$\alpha_s$ obtained are somewhat large in comparison with the experimental
average. The ``missing-doublet'' $SU(5)$, generally, predicts smaller values of
$\alpha_s$. In both versions of the ``missing-doublet'', the high energy
threshold effects on $\alpha_s$ operate in the opposite direction than in the
case of the minimal model, leading to small values. In the case of the
Peccei-Quinn version however the presence of an extra intermediate scale allows
to achieve an excellent agreement with the experimental $\alpha_s$ values.
Finally, the last considered version, with light remnants, exhibits unification
of couplings at string scale at the expense however of rather large $\alpha_s$
values. | hep |
Antimatter in Different Baryogenesis Scenarios: Possible mechanisms of abundant creation of antimatter in the universe are
reviewed. The necessary conditions for that are: baryonic charge
nonconservation, spontaneous breaking of charge symmetry or nonequilibrium
initial state, and the formation of appropriate initial conditions during
inflation. In this case the universe may be populated with domains, cells, or
even stellar size objects consisting of antimatter. | hep |
Neutrino oscillations in high energy cosmic neutrino flux: I discuss the effects of neutrino oscillations on high energy cosmic
neutrinos which come from cosmologically distant astrophysical sources. I
incorporate all the up-to-date constraints from the solar, atmospheric,
reactor, accelerator data and give the possible pattern for the ratio of the
high energy cosmic neutrinos in the cases of three and four neutrino schemes. | hep |
Transverse densities and generalized parton distributions of $ρ$
meson in light front quark model: We have investigated the transverse charge density for longitudinal and
transversely polarized $\rho$ meson in light-front quark model (LFQM). Charge
densities are obtained from the elastic form factors of the $\rho$ meson
calculated in LFQM including the zero-mode contributions. We have computed the
different helicity matrix elements of the $\rho$ meson. In addition to this, we
have also presented the results for the generalized parton distributions (GPDs)
and impact-parameter dependent parton distribution functions (ipdpdfs) of the
$\rho$ meson. | hep |
Classification of symmetric toroidal orbifolds: We provide a complete classification of six-dimensional symmetric toroidal
orbifolds which yield N>=1 supersymmetry in 4D for the heterotic string. Our
strategy is based on a classification of crystallographic space groups in six
dimensions. We find in total 520 inequivalent toroidal orbifolds, 162 of them
with Abelian point groups such as Z_3, Z_4, Z_6-I etc. and 358 with non-Abelian
point groups such as S_3, D_4, A_4 etc. We also briefly explore the properties
of some orbifolds with Abelian point groups and N=1, i.e. specify the Hodge
numbers and comment on the possible mechanisms (local or non-local) of gauge
symmetry breaking. | hep |
Spontaneous Symmetry Breaking in Compactified $λφ^4$ Theory: We consider the massive vector $N$-component $(\lambda\phi^{4})_{D}$ theory
in Euclidian space and, using an extended Matsubara formalism we perform a
compactification on a $d$-dimensional subspace, $d\leq D$. This allows us to
treat jointly the effect of temperature and spatial confinement in the
effective potential of the model, setting forth grounds for an analysis of
phase transitions driven by temperature and spatial boundary. For $d=2$, which
corresponds to the heated system confined between two parallel planes
(separation $L$), we obtain, in the large $N$ limit at one-loop order, formulas
for temperature- and boundary-dependent mass and coupling constant. The
equation for the critical curve in the $\beta \times L$ plane is also derived. | hep |
Hadron energy spectrum in polarized top quark decays considering the
effects of hadron and bottom quark masses: We present the analytical expressions for the next-to-leading order
corrections to the partial decay width $t(\uparrow) \rightarrow bW^+$, followed
by $b\rightarrow H_bX$, for nonzero b-quark mass ($m_b\neq 0$) in the
fixed-flavor-number scheme (FFNs). To make the predictions for the energy
distribution of outgoing hadrons $H_b$, as a function of the normalized
$H_b$-energy fraction $x_H$, we apply the general-mass variable-flavor-number
scheme (GM-VFNs) in a specific helicity coordinate system where the
polarization of top quark is evaluated relative to the b-quark momentum. We
also study the effects of gluon fragmentation and finite hadron mass on the
hadron energy spectrum so that hadron masses are responsible for the low-$x_H$
threshold. In order to describe both the b-quark and the gluon hadronizations
in top decays we apply realistic and nonperturbative fragmentation functions
extracted through a global fit to $e^+e^-$ annihilation data from CERN LEP1 and
SLAC SLC by relying on their universality and scaling violations. | hep |
More about F-term uplifting: We study moduli stabilization and a realization of de Sitter vacua in
generalized F-term uplifting scenarios of the KKLT-type anti-de Sitter vacuum,
where the uplifting sector X directly couples to the light K\"ahler modulus T
in the superpotential through, e.g., stringy instanton effects. F-term
uplifting can be achieved by a spontaneous supersymmetry breaking sector, e.g.,
the Polonyi model, the O'Raifeartaigh model and the Intriligator-Seiberg-Shih
model. Several models with the X-T mixing are examined and qualitative features
in most models {\it even with such mixing} are almost the same as those in the
KKLT scenario. One of the quantitative changes, which are relevant to the
phenomenology, is a larger hierarchy between the modulus mass m_T and the
gravitino mass $m_{3/2}$, i.e., $m_T/m_{3/2} = {\cal O}(a^2)$, where $a \sim 4
\pi^2$. In spite of such a large mass, the modulus F-term is suppressed not
like $F^T = {\cal O}(m_{3/2}/a^2)$, but like $F^T = {\cal O}(m_{3/2}/a)$ for
$\ln (M_{Pl}/m_{3/2}) \sim a$, because of an enhancement factor coming from the
X-T mixing. Then we typically find a mirage-mediation pattern of gaugino masses
of ${\cal O}(m_{3/2}/a)$, while the scalar masses would be generically of
${\cal O}(m_{3/2})$. | hep |
Quarkonium Production At $Z^0$ and in $Υ(1S)$ Decay: The conventional color-singlet model was challenged by the recent data on
quarkonium production. Discrepancies in production rates were observed at the
Tevatron, at LEP, and in fixed-target experiments. The newly advocated
color-octet mechanism provides a plausible solution to the anomalous quarkonium
production observed at the Tevatron. The color-octet mechanism should also
affect other quarkonium production channels. In this paper we will summarize
the studies of quarkonium production in $Z^0$ and $\Upsilon$ decays. | hep |
Leptogluons in dilepton production at LHC: In the composite models with colored substructure of the fermions the color
singlet leptons are accompanied by a composite color octet partners, which are
known as leptogluons. We consider the effect of leptogluons in the dilepton
production at the LHC and show that in the reachable parameter range this
effect is typically dominated by t-channel leptogluon exchange (indirect
channel). We show that this channel alone can give a sizable contribution to
the dimuon production at the LHC for TeV scale values of the invariant mass of
the muon-antimuon pairs. | hep |
Rapidity and Energy Dependences of Temperatures and Volume Extracted
from Identified Charged Hadron Spectra in Proton-Proton Collisions at a Super
Proton Synchrotron (SPS): The standard (Bose-Einstein/Fermi-Dirac or Maxwell-Boltzmann) distribution
from the relativistic ideal gas model is used to study the transverse momentum
($p_{T}$) spectra of identified charged hadrons ($\pi^-$, $\pi^+$, $K^-$,
$K^+$, $\bar p$, and $p$) with different rapidities produced in inelastic
proton-proton ($pp$) collisions at the Super Proton Synchrotron (SPS). The
experimental data measured by the NA61/SHINE Collaboration at the
center-of-mass (c.m.) energies $\sqrt{s}=6.3$, 7.7, 8.8, 12.3, and 17.3 GeV are
fitted well by the distribution. It is shown that the effective temperature
($T_{eff}$ or $T$), kinetic freeze-out temperature ($T_{0}$), and initial
temperature ($T_{i}$) decrease with the increase in rapidity and increase with
the increase in c.m. energy. The kinetic freeze-out volume ($V$) extracted from
the $\pi^-$, $\pi^+$, $K^-$, $K^+$, and $\bar p$ spectra decreases with the
rapidity and increase with the c.m. energy. The opposite tendency of $V$,
extracted from the $p$ spectra, is observed to be increasing with the rapidity
and decreasing with the c.m. energy due to the effect of leading protons. | hep |
Associated Production of a KK-Graviton with a Higgs Boson via Gluon
Fusion at the LHC: In order to solve the hierarchy problem, several extra-dimensional models
have received considerable attention. We have considered a process where a
Higgs boson is produced in association with a KK-graviton ($G_{\rm KK}$) at the
LHC. At the leading order, this process occurs through gluon fusion mechanism
$gg \to h G_{\rm KK}$ via a quark loop. We compute the cross section and
examine some features of this process in the ADD model. We find that the quark
in the loop does not decouple in the large quark-mass limit just as in the case
of $gg\to h$ process. We compute the cross section of this process for the case
of the RS model also. We examine the feasibility of this process being observed
at the LHC. | hep |
$D_s$ Inclusive Decays: The availability of branching fractions for a large majority of $D_s$ decays
permits the prediction of inclusive branching fractions. This is achieved with
the help of a modest amount of input from an isospin statistical model applied
to non-resonant multibody $D_s$ decays. A systematic uncertainty in these
mostly small branching ratios is estimated by comparing predictions of this
model with those of a model involving quark-antiquark pair production. The
calculated inclusive branching fractions can be compared with data (for
example, from a large sample of $D_s^+ D_s^{*-} + D_s^{*+} D_s^-$ obtained by
the CLEO Collaboration) and examined for specific final states which can shed
light on strong and weak decay mechanisms. | hep |
Cosmic-Ray Neutrinos from the Decay of Long-Lived Particle and the
Recent IceCube Result: Motivated by the recent IceCube result, we study high energy cosmic-ray
neutrino flux from the decay of a long-lived particle. Because neutrinos are so
transparent, high energy neutrinos produced in the past may also contribute to
the present neutrino flux. We point out that the PeV neutrino events observed
by IceCube may originate in the decay of a particle much heavier than PeV if
its lifetime is shorter than the present cosmic time. It is shown that the mass
of the particle responsible for the IceCube event can be as large as $\sim
10^{10}\ {\rm GeV}$. We also discuss several possibilities to acquire
information about the lifetime of the long-lived particle. | hep |
Measurement of the pseudoscalar mixing angle and $η^{\prime}$
gluonium content with KLOE detector: We have measured the ratio $R_{\phi}=BR(\phi \to \eta^{\prime}
\gamma)/BR(\phi \to \eta \gamma)$ by looking for the radiative decays $\phi \to
\eta^{\prime} \gamma$ and $\phi \to \eta \gamma$ in the final states
$\pi^+\pi^-$ 7 $\gamma$'s and 7 $\gamma$'s respectively, in a sample of $\sim
1.3\cdot 10^{9}$ $\phi$ mesons produced at the Frascati $\phi$-factory. We
obtain $R_{\phi}=(4.77\pm0.09_{stat}\pm0.19_{sys})\cdot 10^{-3}$ from which we
derive $BR(\phi \to \eta^{\prime}
\gamma)=(6.20\pm0.11_{stat}\pm0.25_{sys})\cdot 10^{-5}$. In the hypothesis of
no gluonium content we extract the pseudoscalar mixing angle in the
quark-flavor basis $\phi_P=(41.4\pm0.3_{stat}\pm0.7_{sys}\pm0.6_{th})^{\circ}$.
Combining the value of $R_{\phi}$ with other constraints, we estimate the
gluonium fractional content of $\eta^{\prime}$ meson as $Z^2 = 0.14\pm0.04$ and
the mixing angle $\phi_P = (39.7\pm0.7)^{\circ}$. | hep |
Effective Supergravity from the Weakly Coupled Heterotic String: The motivation for Calabi-Yau-like compactifications of the weakly coupled
$E_8\otimes E_8$ heterotic string theory, its particle spectrum and the issue
of dilaton stabilization are briefly reviewed. Modular invariant models for
hidden sector condensation and supersymmetry breaking are described at the
quantum level of the effective field theory. Their phenomenological and
cosmological implications, including a possible origin for R-parity, are
discussed. | hep |
Screening in Hot Non-Abelian Plasma: This thesis is devoted to the study of the screening masses in hot
non-Abelian theories. Section 1 contain a brief introduction to the topic. In
section 2 a detailed overview of the screening phenomena and their applications
is given. In section 3 the screening masses are defined through the coupled gap
equations. Section 4 deals with the determination of the screening masses of
hot SU(2) gauge theory in the framework of the 3d lattice adjoint Higgs model
considered as an effective theory. Finally in section 5 the screening masses of
hot SU(2) Higgs model are examined. | hep |
Twist operator correlator revisited and tau function on Hurwitz space: Correlation function of twist operators is a natural quantity of interest in
two-dimensional conformal field theory (2d CFT) and finds relevance in various
physical contexts. For computing twist operator correlators associated with
generic branched covers of genus zero and one, we present a generalization of
the conventional stress-tensor method to encompass generic 2d CFTs without
relying on any free field realization. This is achieved by employing a
generalization of the argument of Calabrese-Cardy in the cyclic genus zero
case. The generalized stress-tensor method reveals a compelling relation
between the twist operator correlator and the tau function on Hurwitz space,
the moduli space of branched covers, of Kokotov-Korotkin. This stems from the
close relation between stress-tensor one-point function and Bergman projective
connection of branched cover. The tau function on Hurwitz space is in turn
related to the more general isomonodromic tau function, and this chain of
correspondence thus relates the twist operator correlator to a canonical
algebro-geometric object and endows it with an integrable system
interpretation. Conversely, the tau function on Hurwitz space essentially
admits a CFT interpretation as the holomorphic part of the twist operator
correlator of $c=1$ free boson. | hep |
Electromagnetic form factors of the $B_c$-like tetraquarks: molecular
and diquark-antidiquark pictures: In this study, we use the molecular and diquark-antidiquark tetraquark
pictures to investigate magnetic and quadrupole moments of the $B_c$-like
ground state tetraquarks with the QCD light-cone sum rules with quantum numbers
$J^P = 1^+$. In the numerical analysis, to obtain the magnetic and quadrupole
moments of $B_c$-like tetraquark states molecular and diquark-antidiquark forms
of interpolating currents, and photon distribution amplitudes have been used.
The magnetic moments are acquired as $ \mu_{Z_{{uc \bar u \bar
b}}}^{Mol}=1.18^{+0.52}_{-0.40}~\mu_N$, $\mu_{Z_{{uc \bar u \bar
b}}}^{Di}=3.05^{+1.19}_{-0.95}~\mu_N$, $\mu_{Z_{dc \bar d \bar
b}}^{Mol}=0.32^{+0.18}_{-0.10}~\mu_N$, and $\mu_{Z_{dc \bar d \bar
b}}^{Di}=2.38^{+0.95}_{-0.75}~\mu_N$. The hadrons' magnetic and quadrupole
moments are another fundamental observable as their mass, which provides
information on the underlying quark structure and dynamics. The results
obtained in both pictures are quite different from each other. Any experimental
measurement of the magnetic moments can provide an understanding of the
internal structure of these states. We get nonzero but small values for the
quadrupole moments of $B_c$-like tetraquark states showing non-spherical charge
distributions. Hopefully, the examinations given in this study will be helpful
to an experimental search of them, which will be an interesting research
subject. | hep |
Recent Developments in the PQCD Approach: We review recent developments in the perturbative QCD approach to exclusive
hadronic B meson decays. We discuss the important next-to-leading-order
corrections to B -> pi K, pi pi, and the penguin-dominated B -> PV modes, where
P (V) is a pseudo-scalar (vector) meson. | hep |
Islands on codim-2 branes in Gauss-Bonnet Gravity: We study the black hole information problem on codim-2 branes in Gauss-Bonnet
gravity. Thanks to the island surface ending on the brane, the Page curve of
eternal black holes can be recovered for all of the GB couplings within the
causal constraints. Our results strongly support the universality of the island
mechanism. Similar to Einstein's gravity, the HM surface can exist only in a
finite time in GB gravity. Remarkably, for various parameters, the maximum
times of HM surface are always larger than the Page times. As a result, the
strange behavior of HM surfaces does not affect the Page curves for general GB
gravity. Finally, we establish the correlation between the Page time, GB
couplings, and brane tension, revealing that the Page time increases with these
factors. | hep |
Late-time Evolution of a Charged Massless Scalar Field in the Spacetime
of a Dilaton Black Hole: We investigate the power-law tails in the evolution of a charged massless
scalar field around a fixed background of a dilaton black hole. Using both
analytical and numerical methods we find the inverse power-law relaxation of
charged fields at future timelike infinity, future null infinity, and along the
outer horizon of the considered black hole. We invisage that a charged hair
decays slower than neutral ones. The oscillatory inverse power law along the
outer horizon of the dilaton black hole is of a great importance for a mass
inflation scenario along the Cauchy horizon of a dynamically formed dilaton
black hole. | hep |
Precise strength of th piNN coupling constant: We report here a preliminary value for the piNN coupling constant deduced
from the GMO sumrule for forward piN scattering. As in our previous
determination from np backward differential scattering cross sections we give a
critical discussion of the analysis with careful attention not only to the
statistical, but also to the systematic uncertainties. Our preliminary
evaluation gives $g^2_c$(GMO) = 13.99(24). | hep |
Exactly Solvable Floquet Dynamics for Conformal Field Theories in
Dimensions Greater than Two: We find classes of driven conformal field theories (CFT) in d+1 dimensions
with d > 1, whose quench and floquet dynamics can be computed exactly. The
setup is suitable for studying periodic drives, consisting of square pulse
protocols for which Hamiltonian evolution takes place with different
deformations of the original CFT Hamiltonian in successive time intervals.
These deformations are realized by specific combinations of conformal
generators with a deformation parameter $\beta$; the $\beta < 1$ ($\beta > 1$)
Hamiltonians can be unitarily related to the standard (L\"uscher-Mack) CFT
Hamiltonians. The resulting time evolution can be then calculated by performing
appropriate conformal transformations. For d <= 3 we show that the
transformations can be easily obtained in a quaternion formalism; we use this
formalism to obtain exact expressions for the fidelity, unequal-time
correlator, and the energy density for the driven system for d = 3. Our results
for a single square pulse drive cycle reveal qualitatively different behaviors
depending on the value of $\beta$, with exponential decays characteristic of
heating for $\beta > 1$, oscillations for $\beta < 1$ and power law decays for
$\beta = 1$. When the Hamiltonians in one cycle involve generators of a single
SL(2, R) subalgebra we find fixed points or fixed surfaces of the corresponding
transformations. Successive cycles lead to either convergence to one of the
fixed points, or oscillations, depending on the conjugacy class. This indicates
that the system can be in different dynamical phases as we vary the parameters
of the drive protocol. We also point out that our results are expected to hold
for a broader class of QFTs that possesses an SL(2,C) symmetry with fields that
transform as quasi-primaries under this. As an example, we briefly comment on
celestial CFTs in this context. | hep |
Chargino Production and Decay in Photon-Photon-Collisions: We study the production and leptonic decay of charginos in collisions of
polarized photon beams including the complete spin correlations. The photons
can be generated by Compton backscattering of polarized laser pulses off a
polarized electron beam. Since the production process is determined alone by
the electromagnetic coupling of the charginos this process allows to study
their decay dynamics. The cross section and the forward-backward asymmetry of
the decay lepton are very sensitive to the gaugino mass parameter $M_1$ and to
the sneutrino mass without any ambiguities. | hep |
Introduction to GPDs and TMDs: Generalised parton distributions (GPDs) and transverse momentum dependent
parton distributions (TMDs) describe complementary aspects of the
three-dimensional structure of hadrons. We discuss their relation to each other
and recall important theory results concerning their properties and their
connection with physical observables. | hep |
A Modern Introduction to Quarkonium Theory: Recent advances in lattice and continuum QCD have given us new insights into
quarkonium physics. These set of lectures are intend for the uninitiated. We
first give a physical picture of quarkonium and describe the hybrids states
established in lattice QCD. Then we give an unorthodox presentation of
Non-Relativistic QCD (NRQCD) including a novel method for the application of
spin-symmetries. Finally we describe the prototypical application of NRQCD:
cancellation of infrared divergences in decays of P-wave quarkonia. | hep |
The Dressing Method as Non Linear Superposition in Sigma Models: We apply the dressing method on the Non Linear Sigma Model (NLSM), which
describes the propagation of strings on $\mathbb{R}\times \mathrm{S}^2$, for an
arbitrary seed. We obtain a formal solution of the corresponding auxiliary
system, which is expressed in terms of the solutions of the NLSM that have the
same Pohlmeyer counterpart as the seed. Accordingly, we show that the dressing
method can be applied without solving any differential equations. In this
context a superposition principle emerges: The dressed solution is expressed as
a non-linear superposition of the seed with solutions of the NLSM with the same
Pohlmeyer counterpart as the seed. | hep |
Evolution of flat universe with a cosmological term in modified
Relativistic Theory of Gravitation as a scalar-tensor extension of General
Relativity: We consider the dynamics of tensor and scalar gravitational fields in the
Relativistic Theory of Gravitation with the Minkowskian vacuum metric and
generalize the formulation to the massless graviton. The potential of scalar
field is determined in the presence of cosmological term under clear physical
motivations. We find cosmological inflationary solutions and analyze conditions
providing the transition to the regime of hot expanding universe. | hep |
The electro-magnetic Form Factors of the Proton in Chiral Soliton Models: The electro-magnetic form factors of the proton are calculated in a chiral
soliton model with relativistic corrections. The magnetic form factor $G_M$ is
shown to agree well with the new SLAC data for spacelike $Q^2$ up to 30
(GeV/c)$^2$ if superconvergence is imposed. The direct continuation through a
Laurent series to the timelike region above the physical threshold is in fair
agreement with the presently available set of data. The electric form factor
$G_E$ is dominated by a zero in the few (GeV/c)$^2$ region which appears to be
in conflict with the SLAC data. | hep |
Probing the photon polarization in $B \to K^*γ$ with conversion: We re-examine the possibility to measure the photon polarization in $B \to
K^*\gamma$ decays, via decays in which the photon subsequently undergoes
nuclear conversion to a lepton pair. We obtain compact expressions for the full
decay-plus-conversion amplitude. With these results we show that interference
between the $B \to (K^*\to K\pi)\gamma$ decay and the $\gamma N \to
\ell^+\ell^-N$ conversion permits both the ratio and relative weak phase
between the left- and right-handed photon amplitudes to be probed by an angular
observable, constructed from the final state dilepton, kaon and pion kinematic
configuration. Exploiting this technique will be experimentally challenging.
However, we present special kinematic cuts that enhance the statistical power
of this technique by an $\mathcal{O}(1)$ factor. We verify this effect and
extract pertinent angular kinematic distributions with dedicated numerical
simulations. | hep |
The diffraction cone shrinkage speed up with the collision energy: The multiperipheral ladder structure of the Pomeron leads to the quite
natural conclusion that the elastic slope Bel is not simple linear function of
the colliding particles energy logarithm. The existing experimental data on the
diffraction cone shrinkage points to such "complicated" dependence indeed. The
shrinkage diffraction cone speed up with the beam energy is directly connected
with an extreme rise of total cross-section (Froissart limit). | hep |
Scale Evolution of Unintegrated Distributions and the p_t Spectrum of
Gauge Bosons: We present predictions for the $Z$-boson $p_t$-spectrum at Tevatron within
the framework of unintegrated distributions evolved according to evolution
equations recently proposed by us. We discuss the dependence of the results on
the choice of non-perturbative parameters, the coupling constant and the impact
of soft gluon resummation. | hep |
Quantum dilaton gravity as a linear dilaton conformal field theory: A model of matter-coupled gravity in two dimensions is quantized. The crucial
requirement for performing the quantization is the vanishing of the conformal
anomaly, which is achieved by tuning a parameter in the interaction potential.
The spectrum of the theory is determined by mapping the model first onto a
field theory with a Liouville interaction, then onto a linear dilaton conformal
field theory. In absence of matter fields a pure gauge theory with massless
ground state is found; otherwise it is possible to minimally couple up to 11
matter scalar fields: in this case the ground state is tachyonic and the matter
sector decouples, like the transverse oscillators in the critical bosonic
string. | hep |
Thermofield Dynamics for Twisted Poincare-Invariant Field Theories: Wick
Theorem and S-matrix: Poincare invariant quantum field theories can be formulated on
non-commutative planes if the statistics of fields is twisted. This is
equivalent to state that the coproduct on the Poincare group is suitably
twisted. In the present work we present a twisted Poincare invariant quantum
field theory at finite temperature. For that we use the formalism of
Thermofield Dynamics (TFD). This TFD formalism is extend to incorporate
interacting fields. This is a non trivial step, since the separation in
positive and negative frequency terms is no longer valid in TFD. In particular,
we prove the validity of Wick's theorem for twisted scalar quantum field at
finite temperature. | hep |
Searches for new physics with leptons and jets at CMS: A variety of models of physics beyond the standard model predict new
particles that decay to leptons, jets, or both together. These models include
axigluons, colorons, diquarks, excited quarks, heavy long-lived charged
particles, leptoquarks, Randall-Sundrum gravitons, string resonances, and new
vector bosons (right-handed W and Z'). Using the data collected in 2011 and
2012 at center-of-mass energies of 7 and 8 TeV, the CMS collaboration has
performed searches for these new particles in channels with leptons and jets.
The results of these searches will be presented. No evidence of new physics has
been observed, and these results set new limits on the parameters of these
models. | hep |
Abelian Gauge Invariance of the WZ-type Coupling in ABJM Theory: We construct the interaction terms between the worldvolume fields of multiple
M2-branes and 3-form gauge field of 11-dimensional supergravity, in the context
of ABJM theory. The obtained Wess-Zumino-type coupling is simultaneously
invariant under the U$_{\textrm{L}}(N)\times$U$_{\textrm{R}}(N)$ non-Abelian
gauge transformation of the ABJM theory and the Abelian gauge transformation of
the 3-form field in 11-dimensional supergravity. | hep |
Collective Coordinate Quantization: Relativistic and Gauge Symmetric
Aspects: The introduction and quantization of a center-of-mass coordinate is
demonstrated for the one-soliton sector of nonlinear field theories in (1+1)
dimensions. The present approach strongly emphazises the gauge and
BRST-symmetry aspects of collective coordinate quantization. A gauge is
presented which is independent of any approximation scheme and which allows to
interpret the new degree of freedom as the {\em quantized} center of mass
coordinate of a soliton. Lorentz invariance is used from the beginning to
introduce fluctuations of the collective coordinate in the {\em rest frame} of
the {\em moving} soliton. It turns out that due to the extended nature of the
soliton retardation effects lead to differences in the quantum mechanics of the
soliton as compared to a point-like particle. Finally, the results of the
semiclassical expansion are used to analyse effective soliton-meson vertices
and the coupling to an external source. Such a coupling in general causes
acceleration as well as internal excitation of the soliton. | hep |
Model independent constraints on leptoquarks from MU and TAU lepton rare
processes: We perform a model independent analysis so as to constrain the leptoquark
(LQ) models from negative searches for $\mu \to e \gamma$, $\mu \to 3e$ decays
(and analogous processes in the $\tau$ sector), and coherent $\mu-e$ conversion
in nuclei. We considerably improve some constraints obtained by analyses known
in the literature, analyses which we show have by far underestimated the LQ
contributions to the $\mu\to 3e$. In particular we find that the coherent
$\mu-e$ conversion in nuclei mediated by the photon--conversion mechanism and
the $\mu \to 3e$ decay are golden plates where the flavor changing leptoquark
couplings, involving the second and third quark generations, can be strongly
constrained. This is due to the fact that these processes get the enhancements
by large $\log(m_q^2/m^2_{LQ})$ terms which are induced by the so-called
``photon-penguin'' diagrams. These enhancements, which produce a mild GIM
suppression in the amplitudes, have not been taken into account in the previous
analyses. We show that the $\mu \to e \gamma$ decay can set weaker constraints
on the LQ models and this is because its amplitude is strongly GIM suppressed
by the terms of order $O(m_q^2/m^2_{LQ})$. We also present the results for the
corresponding constraints in the $\tau$ sector. Finally the prospects of the
future muon experiments for the improvement of the present bounds are analyzed
and discussed. | hep |
Vacua of N=10 three dimensional gauged supergravity: We study scalar potentials and the corresponding vacua of N=10 three
dimensional gauged supergravity. The theory contains 32 scalar fields
parametrizing the exceptional coset space $\frac{E_{6(-14)}}{SO(10)\times
U(1)}$. The admissible gauge groups considered in this work involve both
compact and non-compact gauge groups which are maximal subgroups of
$SO(10)\times U(1)$ and $E_{6(-14)}$, respectively. These gauge groups are
given by $SO(p)\times SO(10-p)\times U(1)$ for $p=6,...10$, $SO(5)\times
SO(5)$, $SU(4,2)\times SU(2)$, $G_{2(-14)}\times SU(2,1)$ and $F_{4(-20)}$. We
find many AdS$_3$ critical points with various unbroken gauge symmetries. The
relevant background isometries associated to the maximally supersymmetric
critical points at which all scalars vanish are also given. These correspond to
the superconformal symmetries of the dual conformal field theories in two
dimensions. | hep |
Inflation in Models with Large Extra Dimensions Driven by a Bulk Scalar
Field: We discuss inflation in models with large extra dimensions, driven by a bulk
scalar field. The brane inflaton is then a single effective field, obtained
from the bulk scalar field by scaling. The self interaction terms of the
effective brane inflaton are then naturally suppressed. The picture is
consistent with a fundamental string scale in the TeV range without the problem
of a superlight inflaton. If hybrid inflation is considered, the right
prediction for the density perturbations as observed by COBE can be obtained
without any fine tunning. The bulk inflaton then decays preferentially into
brane Higgses and reheating follows. | hep |
Exploring Non-Holomorphic Soft Terms in the Framework of Gauge Mediated
Supersymmetry Breaking: It is known that in the absence of a gauge singlet field, a specific class of
supersymmetry (SUSY) breaking non-holomorphic (NH) terms can be soft breaking
in nature so that they may be considered along with the Minimal Supersymmetric
Standard Model (MSSM) and beyond. There have been studies related to these
terms in minimal supergravity based models. Consideration of an F-type SUSY
breaking scenario in the hidden sector with two chiral superfields however
showed Planck scale suppression of such terms. In an unbiased point of view for
the sources of SUSY breaking, the NH terms in a phenomenological MSSM (pMSSM)
type of analysis showed a possibility of a large SUSY contribution to muon
$g-2$, a reasonable amount of corrections to the Higgs boson mass and a drastic
reduction of the electroweak fine-tuning for a higgsino dominated
$\widetilde{\chi}^0_1$ in some regions of parameter space. We first investigate
here the effects of the NH terms in a low scale SUSY breaking scenario. In our
analysis with minimal gauge mediated supersymmetry breaking (mGMSB) we probe
how far the results can be compared with the previous pMSSM plus NH terms based
study. We particularly analyze the Higgs, stop and the electroweakino sectors
focusing on a higgsino dominated $\widetilde{\chi}^0_1$ and
$\widetilde{\chi}^{\pm}_1$, a feature typically different from what appears in
mGMSB. The effect of a limited degree of RG evolutions and vanishing of the
trilinear coupling terms at the messenger scale can be overcome by choosing a
non-minimal GMSB scenario, such as one with a matter-messenger interaction. | hep |
Deviation from tri-bimaximal mixings in two types of inverted
hierarchical neutrino mass models: An attempt is made to explore the possibility for deviations of solar mixing
angle ($\theta_{12}$) from tri-bimaximal mixings, without sacrificing the
predictions of maximal atmospheric mixing angle ($\theta_{23}=\pi/4$) and zero
reactor angle ($\theta_{13}=0$). We find that the above conjecture can be
automatically realised in the inverted hierarchical neutrino mass model having
2-3 symmetry, in the basis where charged lepton mass matrix is diagonal. For
the observed ranges of $\bigtriangleup m^2_{21}$ and $\bigtriangleup m^2_{23]$,
we calculate the predictions on $\tan^2\theta_{12}=0.5, 0.45, 0.35$ for
different input values of the parameters in the neutrino mass matrix. We also
observe a possible crossing over from one type of inverted hierarchical model
having same CP parity (Type-IHA) to other type having opposite CP parity
(Type-IHB). Such neutrino mass matrices can be obtained from the canonical
seesaw formula using diagonal form of Dirac neutrino mass matrix and
non-diagonal texture of right-handed Majorana mass matrix, and may have
important implications in model building using discrete as well as non-abelian
symmetry groups. | hep |
Heavy Quark Photoproduction in Ultra-peripheral Heavy Ion Collisions: Heavy quarks are copiously produced in ultra-peripheral heavy ion collisions.
In the strong electromagnetic fields, c c-bar and b b-bar are produced by
photonuclear and two-photon interactions; hadroproduction can occur in grazing
interactions. We present the total cross sections, quark transverse momentum
and rapidity distributions, as well as the Q Q-bar invariant mass spectra from
the three production channels. We consider AA and pA collisions at the
Relativistic Heavy Ion Collider and Large Hadron Collider. We discuss
techniques for separating the three processes and describe how the AA to pA
production ratios might be measured accurately enough to study nuclear
shadowing. | hep |
Polarizations of two vector mesons in B decays: Inspired by the small longitudinal polarizations (LPs) of $B\to K^* \phi$
decays observed by BELLE and BABAR, we revise the theoretical uncertainties of
perturbative QCD approach for determining hard scales of B decays, we find that
the LPs of $B\to K^* \phi$ could approach to 60% while the branching ratios
(BRs) could be around $9\times 10^{-6}$. In addition, we also study the BRs and
polarization fractions of $B\to \rho (\omega) \rho (\omega)$ and $B\to \rho
(\omega) K^*$ decays. For those tree dominant and color-allowed processes in
$B\to \rho (\omega) \rho (\omega)$ decays, we get that the BRs of $(\rho^{+}
\rho^{-}, \rho^{0} \rho^{+}, \omega \rho^{+})$ are $(23.06, 11.99, 14.78)\times
10^{-6}$ while their LPs are close to unity. Interestingly, due to significant
tree contributions, we find that the BR(LP) of $\rho^{-} K^{*+}$ could be
around $10.13 \times 10^{-6}(60%)$; and due to the tree and electroweak
penguin, the BR(LP) of $\omega K^{*+}$ could be around $5.67 \times
10^{-6}(61%)$. | hep |
$\mathcal{O}(a)$ improved quark mass renormalization for a
non-perturbative matching of HQET to three-flavor QCD: The use of Heavy Quark Effective Theory (HQET) on the lattice as an approach
to B-physics phenomenology is based on a non-perturbative matching of HQET to
QCD in finite volume. As a first step to apply the underlying strategy in the
three-flavor ($N_f = 2+1$) theory, we determine the renormalization constant
and improvement coefficients relating the renormalized current and subtracted
quark mass of (quenched) valence quarks in $\mathcal{O}(a)$ improved $N_f=3$
lattice QCD. We present our strategy and first results for the relevant
parameter region towards weak couplings along a line of constant physics, which
corresponds to lattice resolutions $a\leq 0.02\,$fm and fixes the physical
extent of the matching volume to $L\approx 0.5\,$fm. | hep |
The onset of classical QCD dynamics in relativistic heavy ion collisions: The experimental results on hadron production obtained recently at RHIC offer
a new prospective on the energy dependence of the nuclear collision dynamics.
In particular, it is possible that parton saturation -- the phenomenon likely
providing initial conditions for the multi--particle production at RHIC
energies -- may have started to set in central heavy ion collisions already
around the highest SPS energy. We examine this scenario, and make predictions
based on high density QCD for the forthcoming 22 GeV run at RHIC. | hep |
Conformal group of transformations of the quantum field operators in the
momentum space and the five dimensional Lagrangian approach: Conformal group of transformations in the momentum space, consisting of
translations $p'_{\mu}=p_{\mu}+h_{\mu}$, rotations
$p'_{\mu}=\Lambda^{\nu}_{\mu}p_{\nu}$, dilatation $p'_{\mu}=\lambda p_{\mu}$
and inversion $p'_{\mu}= -M^2p_{\mu}/p^2$ of the four-momentum $p_{\mu}$, is
used for the five dimensional generalization of the equations of motion for the
interacting massive particles. It is shown, that the ${\cal S}$-matrix of the
charged and the neutral particles scattering is invariant under translations in
a four-dimensional momentum space $p'_{\mu}=p_{\mu}+h_{\mu}$. In the suggested
system of equations of motion, the one-dimensional equations over the fifth
coordinate $x_5$ are separated and these one dimensional equations have the
form of the evaluation equations with $x_5=\sqrt{x_o^2-{\bf x}^2}$. The
important property of the derived five dimensional equations of motion is the
explicit separation of the parts of these equations according to the inversion
$p'_{\mu}=-M^2 p_{\mu}/p^{2}$, where $M$ is a scale constant. | hep |
Top-quark decay into Upsilon-meson: The calculation of the partial width of the rare t-quark decay into
Upsilon-meson, W-boson and b-quark (t -> \Upsilon W b) is presented. The
branching ratio equals Br(t -> Upsilon W b) = 1.3 * 10^{-5} that make possible
searches for this rare $t$-quark decay at LHC. | hep |
Minimal Massive Gravity: Conserved Charges, Excitations and the Chiral
Gravity Limit: We find the excitations and construct the conserved charges ( mass and
angular momentum) of the recently found Minimal Massive Gravity (MMG) in 2+1
dimensions in asymptotically Anti-de Sitter (AdS) spacetimes. The field
equation of the theory does not come from an action and hence lacks the
required Bianchi Identity needed to define conserved charges. But the theory,
which also provides a healthy extension of the Topologically Massive Gravity in
the bulk and boundary of spacetime, does admit conserved charges for metric
that are solutions. Our construction is based on background Killing vectors and
imperative to provide physical meaning to the integration constants in the
black hole type metrics. We also study the chiral gravity limit of MMG. | hep |
Fermionic zero modes in the vortex field in arbitrary dimensions and
index of Dirac operator with Majorana-like interaction: In this work we consider fermionic zero modes in the external scalar and
electromagnetic field forming the vortex on a sphere. We find the
correspondence between the equations for the fermions in different dimensions,
find their explicit expressions through the vortex fields in case of massless
fermions, asymptotics near the poles in case of massive fermions and check the
number of the solutions by proving index theorem for the fermions on a sphere.
As a part of deriving the index, we write a detailed calculation of the Green
function of the Heat equation. | hep |
An algebraic model to study the internal structure of pseudo-scalar
mesons with heavy-light quark content: The internal structure of all lowest-lying pseudo-scalar mesons with
heavy-light quark content is studied in detail using an algebraic model that
has been applied recently, and successfully, to the same physical observables
of pseudo-scalar and vector mesons with hidden-flavor quark content, from light
to heavy quark sectors. The algebraic model consists on constructing simple and
evidence-based \emph{ans\"atze} of the meson's Bethe-Salpeter amplitude (BSA)
and quark's propagator in such a way that the Bethe-Salpeter wave function
(BSWF) can then be readily computed algebraically. Its subsequent projection
onto the light front yields the light front wave function (LFWF) whose form
allows us a simple access to the valence-quark Parton Distribution Amplitude
(PDA) by integrating over the transverse momentum squared. We exploit our
current knowledge of the PDAs of lowest-lying pseudo-scalar heavy-light mesons
to compute their Generalized Parton Distributions (GPDs) through the overlap
representation of LFWFs. From these three dimensional knowledge, different
limits/projections lead us to deduce the related Parton Distribution functions
(PDFs), Electromagnetic Form Factors (EFFs), and Impact parameter space GPDs
(IPS-GPDs). When possible, we make explicit comparisons with available
experimental results and earlier theoretical predictions. | hep |
Testing lepton flavor universality in terms of data of BES III and
charm-tau factory: The recent measurements on $R_K$ and $R_{\pi}$ imply that there exists a
possible violation of the leptonic flavor universality which is one of the
cornerstones of the standard model. It is suggested that a mixing between
sterile and active neutrinos might induce such a violation. In this work we
consider the scenarios with one or two sterile neutrinos to explicitly realize
the data while the constraints from the available experiments have been taken
into account. Moreover, as indicated in literature, the deviation of the real
PMNS matrix from the symmetric patterns may be due to a $\mu-\tau$ asymmetry,
therefore the measurements on $R_{D(D_s)e\mu} = \Gamma(D(D_s)\rightarrow
e^+\nu_e)/\Gamma(D(D_s)\rightarrow \mu^+\nu_\mu)$ and $R_{D(D_s)\mu\tau} =
\Gamma(D(D_s)\rightarrow \mu^+\nu_\mu)/\Gamma(D(D_s)\rightarrow
\mu^+\tau_\tau)$ (and for some other heavy mesons $B^{\pm}$ and $B_c$ etc.) may
shed more light on physics responsible for the violation of the leptonic flavor
universality. The data of BES III are available to test the universality and
that of the future charm-tau factory will provide more accurate information
towards the aspect, in this work, we will discuss $R_{D(D_s)e\mu}$ and
$R_{D(D_s)\mu\tau}$ in all details and also briefly consider the cases for
$B^{\pm}$ and $B_c$. | hep |
Bottomonia correlators and spectral functions at zero and finite
temperature: We present preliminary studies of bottomonia spectral functions at zero and
finite temperature using quenched anisotropic lattices. The heavy quark is
treated within Fermilab approach. We find no modification of the $\eta_b$ and
$\Upsilon$ states up to temperatures $2.3T_c$ while our study suggest
dissolution of $\chi_b$ state at $1.15T_c$. | hep |
Hubbard Model with Lüscher fermions: We study the basic features of the two-dimensional quantum Hubbard Model at
half-filling by means of the L\"uscher algorithm and the algorithm based on
direct update of the determinant of the fermionic matrix. We implement the
L\"uscher idea employing the transfer matrix formalism which allows to
formulate the problem on the lattice in $(2+1)$ dimensions. We discuss the
numerical complexity of the L\"uscher technique, systematic errors introduced
by polynomial approximation and introduce some improvements which reduce long
autocorrelations. In particular we show that preconditioning of the fermionic
matrix speeds up the algorithm and extends the available range of parameters.
We investigate the magnetic and the one-particle properties of the Hubbard
Model at half-filling and show that they are in qualitative agreement with the
existing Monte Carlo data and the mean-field predictions. | hep |
Tension of Confining Strings at Low Temperature: In the low temperature confining phase of QCD or QCD-like theories it is
challenging to capture the temperature dependence of observables through
AdS/CFT. Using the blackfold approach we compute the quark-antiquark linear
static potential in the low temperature confining phase, taking into account
the thermal excitations of the string. We find the explicit temperature
dependence of the string tension and notice that, as naturally expected,
tension decreases as temperature increases. We have also generalized the
blackfold approach for the computation of the Wilson loops, making it directly
applicable to a large class of backgrounds. | hep |
M(atrix) Theory on T9/Z2 Orbifold and Twisted Zero Brane: M(atrix) theory compactified on an orbifold ${\bf T}_9/{\bf Z}_2$ is studied.
Via zero-brane parton scattering we find that each of the $2^9 = 512$ orbifold
fixed points carry $-1/32$ units of zero-brane charge. The anomalous flux is
cancelled by introducing a twisted sector consisting of 32 zero-branes that are
spacetime supersymmetry singlets. These twisted sector zero-branes are nothing
but gravitational waves propagating along the M-theory direction. There is no
D0-partons in the untwisted sector, a fact consistent with holographic
principle. For low-energy excitations, the orbifold compactification is
described by ten-dimensional supersymmetric Yang-Mills theory with gauge group
$SO(32)$. | hep |
Measurement of B Decays to phi K gamma: We search for the decays B- -> phi K- gamma and B0bar -> phi K0bar gamma in a
data sample of 228 million BBbar pairs collected at the Upsilon(4S) resonance
with the BaBar detector. We measure the branching fraction B(B- -> phi K-
gamma) = (3.5 +/- 0.6 +/- 0.4) x 10^-6 and set an upper limit B(B0bar -> phi
K0bar gamma) < 2.7 x 10^-6 at the 90% confidence level. We also measure the
direct CP asymmetry in B- -> phi K- gamma, A_CP = (-26 +/- 14 +/- 5)%. The
uncertainties are statistical and systematic, respectively. | hep |
First implementation of transverse spherocity analysis for heavy-ion
collisions at the Large Hadron Collider energies: Transverse spherocity, an event shape observable, has a very unique
capability to separate the events based on their geometrical shape, i.e. jetty
and isotropic. In this work, we use transverse spherocity for the first time in
heavy-ion collisions using A Multi-Phase Transport Model (AMPT). We obtain the
transverse momentum spectra, integrated yield, mean transverse momentum and
azimuthal anisotropy for identified particles in Xe-Xe collisions at
$\sqrt{s_{\rm{NN}}} = 5.44$ TeV and Pb-Pb collisions at $\sqrt{s_{\rm{NN}}} =
5.02$ TeV. The indication of collectivity in heavy-ion collisions can be
clearly seen while comparing the transverse momentum spectra from jetty and
isotropic events. The elliptic flow as a function of transverse spherocity
shows that the isotropic events have nearly zero elliptic flow and the elliptic
flow is mostly dominated by the jetty events. This study will pave a way to
focus on jetty events in heavy-ion collisions in order to investigate jet
medium modification and jet hadro-chemistry in a sophisticated manner. | hep |
Infrared structures of scattering on self-dual radiative backgrounds: The scattering of gluons and gravitons in trivial backgrounds is endowed with
many surprising infrared features which have interesting conformal
interpretations on the two-dimensional celestial sphere. However, the fate of
these structures in more general asymptotically flat backgrounds is far from
clear. In this paper, we consider holomorphic infrared structures in the
presence of non-perturbative, self-dual background gauge and gravitational
fields which are determined by freely specified radiative data. We make use of
explicit formulae for tree-level gluon and graviton scattering in these
self-dual radiative backgrounds, as well as chiral twistor sigma model
descriptions of the classical dynamics. Remarkably, we find that the leading
holomorphic part of tree-level collinear splitting functions -- or celestial
OPEs -- and infinite-dimensional chiral soft algebras are undeformed by the
background. We also compute all-order holomorphic celestial OPEs in the MHV
sectors of gauge theory and gravity. | hep |
Dispersion-theoretical analysis of the electromagnetic form factors of
the $Λ$ hyperon: The electromagnetic form factors of the $\Lambda$ hyperon in the time-like
region are determined precisely through a dispersion-theoretical analysis of
the world data for the cross section of the annihilation process $e^+e^-\to
\bar{\Lambda}{\Lambda}$. The spectral function is represented by a
superposition of narrow and broad vector meson poles. We test different
scenarios for the spectral function and obtain a good description of the world
data in the time-like region. The uncertainties in the extracted form factors
are estimated by means of the bootstrap sampling method. The analytical
continuation of the form factors to the space-like region introduces large
errors due to the lack of data. When the electric $\Lambda$ radius from chiral
perturbation theory is taken as a constraint, the magnetic radius is predicted
as $r_M = 0.681 \pm 0.002$ fm. We also extract various vector meson to baryon
coupling constants. | hep |
(Quasi-) de Sitter solutions across dimensions and the TCC bound: In this work, we investigate the existence of string theory solutions with a
$d$-dimensional (quasi-) de Sitter spacetime, for $3 \leq d \leq 10$.
Considering classical compactifications, we derive no-go theorems valid for
general $d$. We use them to exclude (quasi-) de Sitter solutions for $d \geq
7$. In addition, such solutions are found unlikely to exist in $d=6,5$. For
each no-go theorem, we further compute the $d$-dependent parameter $c$ of the
swampland de Sitter conjecture, $M_p \frac{|\nabla V|}{V} \geq c$. Remarkably,
the TCC bound $c \geq \frac{2}{\sqrt{(d-1)(d-2)}}$ is then perfectly satisfied
for $d \geq 4$, with several saturation cases. However, we observe a violation
of this bound in $d=3$. We finally comment on related proposals in the
literature, on the swampland distance conjecture and its decay rate, and on the
so-called accelerated expansion bound. | hep |
Matching the circular Wilson loop with dual open string solution at
1-loop in strong coupling: We compute the 1-loop correction to the effective action for the string
solution in AdS_5 x S^5 dual to the circular Wilson loop. More generically, the
method we use can be applied whenever the two dimensional spectral problem
factorizes, to regularize and define the fluctuation determinants in terms of
solutions of one-dimensional differential equations. A such it can be applied
to non-homogeneous solutions both for open and closed strings and to various
boundary conditions. In the case of the circular Wilson loop, we obtain, for
the 1-loop partition function a result which up to a factor of two matches the
expectation from the exact gauge theory computation. The discrepancy can be
attributed to an overall constant in the string partition function coming from
the normalization of zero modes, which we have not fixed. | hep |
The spin structure of the Lambda hyperon in quenched lattice QCD: It has been suggested to use the production of Lambda hyperons for
investigating the nucleon spin structure. The viability of this idea depends
crucially on the spin structure of the Lambda. Using nonperturbatively O(a)
improved Wilson fermions in the quenched approximation we have studied matrix
elements of two-quark operators in the Lambda. We present results for the axial
vector current, which give us the contributions of the u, d, and s quarks to
the Lambda spin. | hep |
Searching for New Physics via CP Violation in B -> pi pi: We show how B -> pi pi decays can be used to search for new physics in the b
-> d flavour-changing neutral current. One needs one piece of theoretical
input, which we take to be a prediction for P/T, the ratio of the penguin and
tree amplitudes in Bd -> pi+ pi-. If present, new physics can be detected over
most of the parameter space. If \alpha (\phi_2) can be obtained independently,
measurements of B+ -> pi+ pi0 and Bd/Bd(bar) -> pi0 pi0 are not even needed. | hep |
Spin Polarisation of $t\bar{t}γγ$ production at NLO+PS with
GoSam interfaced to MadGraph5_aMC@NLO: We present an interface between the multipurpose NLO Monte Carlo tool
MadGraph5_aMC@NLO and the automated one-loop amplitude generator GoSam. As a
first application of this novel framework, we compute the NLO corrections to
$pp \to t\bar{t}H$ and $pp \to t\bar{t}\gamma\gamma$ matched to a parton
shower. In the phenomenological analyses of these processes, we focus our
attention on observables which are sensitive to the polarisation of the top
quarks. | hep |
On the physical meaning of the Unruh effect: We present simple arguments that detectors moving with constant acceleration
(even acceleration for a finite time) should detect particles. The effect is
seen to be universal. Moreover, detectors undergoing linear acceleration and
uniform, circular motion both detect particles for the same physical reason. We
show that if one uses a circularly orbiting electron in a constant external
magnetic field as the Unruh--DeWitt detector, then the Unruh effect physically
coincides with the experimentally verified Sokolov--Ternov effect. | hep |
Entanglement negativity in Galilean conformal field theories: We obtain the entanglement negativity for various bipartite zero and finite
temperature pure and mixed state configurations in a class of
$(1+1)$-dimensional Galilean conformal field theories. In this context we
establish a construction for computing the entanglement negativity for such
bipartite states involving a suitable replica technique. Our construction
exactly reproduces certain universal features observed for entanglement
negativity of corresponding states in relativistic $(1+1)$-dimensional
conformal field theories. | hep |
Determining alpha_s from the hyperfine splitting mUpsilon(1S)-mEta(b): The measurement of the eta_b mass, together with a QCD result for the
hyperfine splitting E_{HFS}=M_{Upsilon(1S)}-M_{eta_b}, allows us to determine
the strong coupling constant alpha_s at a low energy scale. The result
alpha_s(M_{Upsilon(1S)})=0.197\pm 0.002_{Delta E_{HFS}^{exp}} \pm
0.002_{scheme} \pm 0.002_{delta <G^2>} \pm 0.006_{delta m_b} \pm 0.005_{ho},
alpha_s(M_{Z^0})=0.124\pm 0.001_{Delta E_{HFS}^{exp}} \pm 0.001_{scheme} \pm
0.001_{delta <G^2>} \pm 0.003_{delta m_b} \pm 0.002_{ho}, is compatible with
the current world average of alpha_s reported by the Particle Data Group, and
shows that the experimental lowest-lying \bar b b hyperfine splitting can be
reproduced in terms of a perturbative and nonperturbative QCD contribution. | hep |
The critical points of lattice QCD with a non--zero quark density: We study the interplay of quark number density and chiral symmetry in lattice
QCD. We suggest that both are controlled by the eigenvalue spectrum of the
fermionic propagator matrix, which shapes the pattern of zeros of the partition
function. The onset of the quark current would be triggered by the lowest lying
eigenvalue, the chiral transition by the density of zeros, the two critical
points being distinct in full QCD, and coincident in the quenched
approximation. Our preliminary estimate for the critical point in full QCD in
the infinite couling limit compares favourably with the predictions of the
strong coupling expansions and of numerical simulations based on exact,
alternative representations of the partition function. Several reasons of
perplexity however remain, which are briefly discussed. | hep |
Null bootstrap for non-Hermitian Hamiltonians: A stable physical system has an energy spectrum that is bounded from below.
For quantum systems, the dangerous states of unboundedly low energies should
decouple and become null. We propose the principle of nullness and apply it to
the bootstrap study of Hermitian and non-Hermitian anharmonic oscillators. | hep |
Expanding running coupling effects in the hard Pomeron: We study QCD hard processes at scales of order k^2 > Lambda^2 in the limit in
which the beta-function coefficient - b is taken to be small, but alphas(k) is
kept fixed. The (nonperturbative) Pomeron is exponentially suppressed in this
limit, making it possible to define purely perturbative high-energy Green's
functions. The hard Pomeron exponent acquires diffusion and running coupling
corrections which can be expanded in the b parameter and turn out to be
dependent on the effective coupling b alphas^2 Y. We provide a general setup
for this b-expansion and we calculate the first few terms both analytically and
numerically. | hep |
Hadroproduction of Charm and Beauty: Recent results on the hadroproduction of charm and beauty are discussed in
the context of the current theoretical and experimental status. The areas
covered include production of open charm and beauty particles and charm and
beauty quarkonia. Experimental results from both fixed target and colliding
beam experiments are presented and compared to theoretical predictions.
Predictions based on QCD perturbation theory are generally successful in
explaining the shapes of differential cross sections but underestimate the
scale of the cross section by factors of 2-3. An exception is production of the
vector meson quarkonia which cannot be satisfactorily explained by perturbative
processes alone. | hep |
Gauge/gravity dual dynamics for the strongly coupled sector of composite
Higgs models: A holographic model of chiral symmetry breaking is used to study the dynamics
plus the meson and baryon spectrum of the underlying strong dynamics in
composite Higgs models. The model is inspired by top-down D-brane
constructions. We introduce this model by applying it to $N_f=2$ QCD. We
compute meson masses, decay constants and the nucleon mass. The spectrum is
improved by including higher dimensional operators to reflect the UV physics of
QCD. Moving to composite Higgs models, we impose perturbative running for the
anomalous dimension of the quark condensate in a variety of theories with
varying number of colors and flavours. We compare our results in detail to
lattice simulations for the following theories: $SU(2)$ gauge theory with two
Dirac fundamentals; $Sp(4)$ gauge theory with fundamental and sextet matter;
and $SU(4)$ gauge theory with fundamental and sextet quarks. In each case, the
holographic results are encouraging since they are close to lattice results for
masses and decay constants. Moreover, our models allow us to compute additional
observables not yet computed on the lattice, to relax the quenched
approximation and move to the precise fermion content of more realistic
composite Higgs models not possible on the lattice. We also provide a new
holographic description of the top partners including their masses and
structure functions. With the addition of higher dimension operators, we show
the top Yukawa coupling can be made of order one, to generate the observed top
mass. Finally, we predict the spectrum for the full set of models with top
partners proposed by Ferretti and Karateev. | hep |
Framed M-branes, corners, and topological invariants: We uncover and highlight relations between the M-branes in M-theory and
various topological invariants: the Hopf invariant over $\mathbb{Q}$,
$\mathbb{Z}$ and $\mathbb{Z}_2$, the Kervaire invariant, the $f$-invariant, and
the $\nu$-invariant. This requires either a framing or a corner structure. The
canonical framing provides a minimum for the classical action and the change of
framing encodes the structure of the action and possible anomalies. We
characterize the flux quantization condition on the C-field and the topological
action of the M5-brane via the Hopf invariant, and the dual of the C-field as
(a refinement of) an element of Hopf invariant two. In the signature
formulation, the contribution to the M-brane effective action is given by the
Maslov index of the corner. The Kervaire invariant implies that the effective
action of the M5-brane is quadratic. Our study leads to viewing the self-dual
string, which is the boundary of the M2-brane on the M5-brane worldvolume, as a
string theory in the sense of cobordism of manifolds with corners. We show that
the dynamics of the C-field and its dual are encoded in unified way in the
4-sphere, which suggests the corresponding spectrum as the generalized
cohomology theory describing the fields. The effective action of the corner is
captured by the $f$-invariant, which is an invariant at chromatic level two.
Finally, considering M-theory on manifolds with G_2 holonomy we show that the
canonical ${\rm G}_2$ structure minimizes the topological part of the M5-brane
action. This is done via the $\nu$-invariant and a variant that we introduce
related to the one-loop polynomial. | hep |
Dark Matter and Torsion: Superheavy right-handed Majorana neutrinos are proposed as a promising
candidate for dark matter, with dynamical axial torsion as the mediating agent. | hep |
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