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Evidence for $B^0 \to χ_{c1} π^0$ at Belle: We present a measurement of the branching fraction for the Cabibbo- and
color-suppressed $B^0 \to \chi_{c1}\pi^0$ decay based on a data sample of
$657\times 10^6$ $B\bar B$ events collected at the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We
observe a signal of $40\pm9$ events with a significance of $4.7\sigma$
including systematic uncertainties. The measured branching fraction is
$\mathcal {B}(B^0 \to \chi_{c1} \pi^0) = (1.12\pm 0.25(\rm {stat.})\pm
0.12({\rm syst.}))\times 10^{-5}$. | hep-ex |
The differential production cross section of the phi(1020) meson in
sqrt(s)=7 TeV pp collisions measured with the ATLAS detector: A measurement is presented of the phi to K+K- production cross section at
sqrt(s) = 7 TeV using pp collision data corresponding to an integrated
luminosity of 383 mub-1, collected with the ATLAS experiment at the LHC.
Selection of phi(1020) mesons is based on the identification of charged kaons
by their energy loss in the pixel detector. The differential cross section is
measured as a function of the transverse momentum, pTphi, and rapidity, |yphi|,
of the phi(1020) meson in the fiducial region 500 < pTphi< 1200 MeV, |yphi| <
0.8, kaon pTK> 230 MeV and kaon momentum pK< 800 MeV.The integrated
phi(1020)-meson production cross section in this fiducial range is measured to
be s(phi K+K-) = 570 pm 8 (stat) pm 66 (syst) pm 20 (lumi) mub. | hep-ex |
New physics limits from kaon decays: Searches for lepton flavour violation and lepton number violation in kaon
decays by the NA62 and NA48/2 experiments at CERN are presented. A new
measurement of the ratio of charged kaon leptonic decay rates
$R_K=\Gamma(K_{e2})/\Gamma(K_{\mu2})$ to sub-percent relative precision is
discussed. An improved upper limit on the lepton number violating
$K^\pm\rightarrow\pi^\mp\mu^\pm\mu^\pm$ decay rate is also reported. The future
10% precision measurement of the branching ratio of the ultra-rare kaon decay
$K^+\rightarrow\pi^+\nu\bar{\nu}$ with the NA62 experiment is finally reviewed. | hep-ex |
Limits on Interactions between Weakly Interacting Massive Particles and
Nucleons Obtained with NaI(Tl) crystal Detectors: Limits on the cross section for weakly interacting massive particles (WIMPs)
scattering off nucleons in the NaI(Tl) detectors at the Yangyang Underground
Laboratory are obtained with a 2967.4 kg*day data exposure. Nuclei recoiling
are identified by the pulse shape of scintillating photon signals. Data are
consistent with no nuclear recoil hypothesis, and 90% confidence level upper
limits are set. These limits partially exclude the DAMA/LIBRA region of
WIMP-sodium interaction with the same NaI(Tl) target detector. This 90%
confidence level upper limit on WIMP-nucleon spin-independent cross section is
3.26*10^-4 pb for a WIMP mass at 10 GeV/c^2. | hep-ex |
A Combined $ν_μ\to ν_e$ and $\barν_μ\to \barν_e$
Oscillation Analysis of the MiniBooNE Excesses: The MiniBooNE experiment at Fermilab reports results from an analysis of the
combined $\nu_e$ and $\bar \nu_e$ appearance data from $6.46 \times 10^{20}$
protons on target in neutrino mode and $11.27 \times 10^{20}$ protons on target
in antineutrino mode. A total excess of $240.3 \pm 34.5 \pm 52.6$ events ($3.8
\sigma$) is observed from combining the two data sets in the energy range
$200<E_\nu^{QE}<1250$ MeV. In a combined fit for CP-conserving $\nu_\mu
\rightarrow \nu_e$ and $\bar{\nu}_{\mu}\rightarrow\bar{\nu}_e$ oscillations via
a two-neutrino model, the background-only fit has a $\chi^2$-probability of
0.03% relative to the best oscillation fit. The data are consistent with
neutrino oscillations in the $0.01 < \Delta m^2 < 1.0$ eV$^2$ range and with
the evidence for antineutrino oscillations from the Liquid Scintillator
Neutrino Detector (LSND). | hep-ex |
Lepton Flavor Violating Decays - Review & Outlook: Here I review the status and prospects of experimental investigations into
lepton flavor violation (LFV) in charged leptons. Rare LFV processes are
naturally expected to occur through loops of TeV scale particles predicted by
supersymmetric theories or other models beyond the Standard Model. In contrast
to physics of quark flavors that is dominated by the Cabibbo-Kobayashi-Maskawa
matrix, LFV in charged leptons is a definitive signal of new physics. Currently
active researches are rare tau decay searches at the B factories. The MEG
experiment will soon start a sensitive search for the LFV muon decay, mu to e
gamma. Prospects for searches at the LHC, a possibility of a fixed target LFV
experiment with high energy muons, and a sensitivity of leptonic kaon decays to
LFV are also briefly discussed. | hep-ex |
Search for the Proton Decay Mode proton to neutrino K+ in Soudan 2: We have searched for the proton decay mode proton to neutrino K+ using the
one-kiloton Soudan 2 high resolution calorimeter. Contained events obtained
from a 3.56 kiloton-year fiducial exposure through June 1997 are examined for
occurrence of a visible K+ track which decays at rest into mu+ nu or pi+ pi0.
We found one candidate event consistent with background, yielding a limit,
tau/B > 4.3 10^{31} years at 90% CL with no background subtraction. | hep-ex |
Proposal to Search for Heavy Neutral Leptons at the SPS: A new fixed-target experiment at the CERN SPS accelerator is proposed that
will use decays of charm mesons to search for Heavy Neutral Leptons (HNLs),
which are right-handed partners of the Standard Model neutrinos. The existence
of such particles is strongly motivated by theory, as they can simultaneously
explain the baryon asymmetry of the Universe, account for the pattern of
neutrino masses and oscillations and provide a Dark Matter candidate.
Cosmological constraints on the properties of HNLs now indicate that the
majority of the interesting parameter space for such particles was beyond the
reach of the previous searches at the PS191, BEBC, CHARM, CCFR and NuTeV
experiments. For HNLs with mass below 2 GeV, the proposed experiment will
improve on the sensitivity of previous searches by four orders of magnitude and
will cover a major fraction of the parameter space favoured by theoretical
models.
The experiment requires a 400 GeV proton beam from the SPS with a total of
2x10^20 protons on target, achievable within five years of data taking. The
proposed detector will reconstruct exclusive HNL decays and measure the HNL
mass. The apparatus is based on existing technologies and consists of a target,
a hadron absorber, a muon shield, a decay volume and two magnetic
spectrometers, each of which has a 0.5 Tm magnet, a calorimeter and a muon
detector. The detector has a total length of about 100 m with a 5 m diameter.
The complete experimental set-up could be accommodated in CERN's North Area.
The discovery of a HNL would have a great impact on our understanding of
nature and open a new area for future research. | hep-ex |
Observation of 1^-0^- Final States from psi(2S) Decays and e^+e^-
Annihilation: Using CLEO data collected from CESR e+e- collisions at the Psi(2S) resonance
and nearby continuum at E_CM=3.67GeV, we report the first significantly
non-zero measurements of light vector-pseudoscalar hadron pair production
(including RhoPi, OmegaPi, RhoEta, and K*0K0bar) and the Pi+Pi-Pi0 final state,
both from Psi(2S) decays and direct e+e- annihilation. | hep-ex |
IceCube Sterile Neutrino Searches: Anomalies in short baseline experiments have been interpreted as evidence for
additional neutrino mass states with large mass splittings from the known,
active flavors. This explanation mandates a corresponding signature in the muon
neutrino disappearance channel, which has yet to be observed. Searches for muon
neutrino disappearance at the IceCube neutrino telescope presently provide the
strongest limits in the space of mixing angles for eV-scale sterile neutrinos.
This proceeding for the Very Large Volume Neutrino Telescopes (VLVnT) Workshop
summarizes the IceCube analyses that have searched for sterile neutrinos and
describes ongoing work toward enhanced, high-statistics sterile neutrino
searches. | hep-ex |
Search for the Decay $B_s^0 \rightarrow η^\prime η$: We report the results of the first search for the decay $B_s^0 \rightarrow
\eta^\prime \eta$ using $121.4~\textrm{fb}^{-1}$ of data collected at the
$\Upsilon(5S)$ resonance with the Belle detector at the KEKB asymmetric-energy
$e^+e^-$ collider. We observe no significant signal and set a 90\%
confidence-level upper limit of %$7.1 \times 10^{-5}$ $6.5 \times 10^{-5}$ on
the branching fraction of this decay. | hep-ex |
b-Jet Identification in the D0 Experiment: Algorithms distinguishing jets originating from b quarks from other jet
flavors are important tools in the physics program of the D0 experiment at the
Fermilab Tevatron p-pbar collider. This article describes the methods that have
been used to identify b-quark jets, exploiting in particular the long lifetimes
of b-flavored hadrons, and the calibration of the performance of these
algorithms based on collider data. | hep-ex |
Search for multi-messenger signals in NOvA coincident with LIGO/Virgo
detections: Using the NOvA neutrino detectors, a broad search has been performed for any
signal coincident with 28 gravitational wave events detected by the LIGO/Virgo
Collaboration between September 2015 and July 2019. For all of these events,
NOvA is sensitive to possible arrival of neutrinos and cosmic rays of GeV and
higher energies. For five (seven) events in the NOvA Far (Near) Detector,
timely public alerts from the LIGO/Virgo Collaboration allowed recording of
MeV-scale events. No signal candidates were found. | hep-ex |
Search for single production of vector-like quarks decaying into $Wb$ in
$pp$ collisions at $\sqrt{s} =$ 8 TeV with the ATLAS detector: A search for singly produced vector-like $Q$ quarks, where $Q$ can be either
a $T$ quark with charge $+2/3$ or a $Y$ quark with charge $-4/3$, is performed
in proton-proton collisions recorded with the ATLAS detector at the LHC. The
dataset corresponds to an integrated luminosity of 20.3 fb$^{-1}$ and was
produced with a centre-of-mass energy of $\sqrt{s}=8$ TeV. This analysis
targets $Q \to Wb$ decays where the $W$ boson decays leptonically. A veto on
massive large-radius jets is used to reject the dominant $t\bar{t}$ background.
The reconstructed $Q$-candidate mass, ranging from 0.4 to 1.2 TeV, is used in
the search to discriminate signal from background processes. No significant
deviation from the Standard Model expectation is observed, and limits are set
on the $Q \to Wb$ cross-section times branching ratio. The results are also
interpreted as limits on the $QWb$ coupling and the mixing with the Standard
Model sector for a singlet $T$ quark or a $Y$ quark from a doublet. $T$ quarks
with masses below 0.95 TeV are excluded at 95% confidence level, assuming a
unit coupling and a BR$(T\rightarrow Wb) = 0.5$, whereas the expected limit is
1.10 TeV. | hep-ex |
Re-discovery of the top quark at the LHC and first measurements: This paper describes the top quark physics measurements that can be performed
with the first LHC data in the ATLAS and CMS experiments. | hep-ex |
Amplitude analysis and branching-fraction measurement of $D_{s}^{+} \to
π^{+}π^{0}η^{\prime}$: Using data collected with the BESIII detector in $e^+e^-$ collisions at
center-of-mass energies between 4.178 and 4.226 GeV and corresponding to
6.32~fb$^{-1}$ of integrated luminosity, we report the amplitude analysis and
branching-fraction measurement of the $D^+_s \to \pi^+ \pi^0 \eta^{\prime}$
decay. We find that the dominant intermediate process is $D^+_s \to\rho^+
\eta^{\prime}$ and the significances of other resonant and nonresonant
processes are all less than $3\sigma$. The upper limits on the branching
fractions of $S$-wave and $P$-wave nonresonant components are set to $0.10\%$
and $0.74\%$ at the $90\%$ confidence level, respectively. In addition, the
branching fraction of the $D^+_s \to \pi^+ \pi^0 \eta^{\prime}$ decay is
measured to be $(6.15\pm0.25(\rm stat.)\pm0.18(\rm syst.))\%$, which receives
significant contribution only from $D_s^+\to \rho^+\eta^{\prime}$ according to
the amplitude analysis. | hep-ex |
Learning New Physics from Data -- a Symmetrized Approach: Thousands of person-years have been invested in searches for New Physics
(NP), the majority of them motivated by theoretical considerations. Yet, no
evidence of beyond the Standard Model (BSM) physics has been found. This
suggests that model-agnostic searches might be an important key to explore NP,
and help discover unexpected phenomena which can inspire future theoretical
developments. A possible strategy for such searches is identifying asymmetries
between data samples that are expected to be symmetric within the Standard
Model (SM). We propose exploiting neural networks (NNs) to quickly fit and
statistically test the differences between two samples. Our method is based on
an earlier work, originally designed for inferring the deviations of an
observed dataset from that of a much larger reference dataset. We present a
symmetric formalism, generalizing the original one; avoiding fine-tuning of the
NN parameters and any constraints on the relative sizes of the samples. Our
formalism could be used to detect small symmetry violations, extending the
discovery potential of current and future particle physics experiments. | hep-ex |
Diffractive Structure Functions from the H1 and ZEUS Experiments at HERA: The cross section of inclusive diffractive process ep -> eXp was measured
within a wide kinematic range in the H1 and ZEUS experiments at HERA. Results
obtained by different experiments and methods are compatible within measurement
uncertainties. The measurements were subjected to DGLAP next-to-leading order
QCD global fits and the diffractive parton distribution functions (DPDFs) of
the proton were determined with noticeably reduced uncertainties due to very
high precision of the data. The gluon density precision was much improved in
fits which also included data on dijet production in diffractive DIS.
Predictions based on the determined DPDFs are in agreement with the measured
inclusive cross-section of diffractive dijet photoproduction and charm
production in diffractive DIS at HERA. The longitudinal diffractive structure
function $F^D_L$ was measured directly for the first time. | hep-ex |
Measurement Of Continuum Dimuon Production In 800-GeV/C Proton-Nucleon
Collisions: Fermilab Experiment 866 has performed an absolute measurement of continuum
dimuon (Drell-Yan) cross sections in 800-GeV/c $pp$ and $pd$ interactions.
Results differential in the mass, Feynman-$x$ ($x_F$) and transverse momenta
($p_T$) of the dimuon pairs are reported. These results represent the most
extensive study of the Drell-Yan process to date, based on a data sample of
175,000 dimuon events covering the widest range in kinematics yet achieved
($4.2 \leq M \leq 16.85$ GeV and $-0.05 \leq x_F \leq 0.8$) with this level of
precision. The cross sections are primarily sensitive to the magnitude and
shape of the light antiquark distributions ($\bar{d}(x)$ and $\bar{u}(x)$) in
the nucleon, but also provide important information on the valence quarks as
well as the gluons. They are in good agreement with other existing
proton-induced Drell-Yan experiments. There is also general agreement between
the data and next-to-leading-order calculations based on various sets of parton
distribution functions. Differences between data and theory are examined, and
the potential impact of these data on future parameterizations of the parton
distributions are discussed. | hep-ex |
Search for magnetic monopoles and stable particles with high electric
charges in 8 TeV $pp$ collisions with the ATLAS detector: A search for highly ionizing particles produced in proton-proton collisions
at 8 TeV center-of-mass energy is performed by the ATLAS collaboration at the
CERN Large Hadron Collider. The dataset used corresponds to an integrated
luminosity of 7.0 fb$^{-1}$. A customized trigger significantly increases the
sensitivity, permitting a search for such particles with charges and energies
beyond what was previously accessible. No events were found in the signal
region, leading to production cross section upper limits in the mass range
200--2500 GeV for magnetic monopoles with magnetic charge in the range
$0.5g_{D}<|g|<2.0g_{D}$, where $g_{D}$ is the Dirac charge, and for stable
particles with electric charge in the range $10<|z|<60$. Model-dependent limits
are presented in given pair-production scenarios, and model-independent limits
are presented in fiducial regions of particle energy and pseudorapidity. | hep-ex |
Measurement of the energy dependence of hadronic jet rates and the
strong coupling alpha_s from the four-jet rate with the DELPHI detector at
LEP: Hadronic events from the data collected with the DELPHI detector at LEP
within the energy range from 89 GeV to 209 GeV are selected, their jet rates
are determined and compared to predictions of four different event generators.
One of them is the recently developed APACIC++ generator which performs a
massive matrix element calculation matched to a parton shower followed by
string fragmentation. The four-jet rate is used to measure alpha_s in the
next-to-leading-order approximation yielding alpha_s(M_Z^2) = 0.1175 +/-
0.0030. The running of alpha_s determined by using four-jet events has been
tested. The logarithmic energy slope is measured to be d\alpha_s^{-1} / d\log
E_{cm} = 1.14 +/- 0.36. Since the analysis is based on four-jet final states it
represents an alternative approach to previous DELPHI alpha_s measurements
using event shape distributions. | hep-ex |
Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix
Element Method and in situ Jet Energy Calibration: A precision measurement of the top quark mass m_t is obtained using a sample
of ttbar events from ppbar collisions at the Fermilab Tevatron with the CDF II
detector. Selected events require an electron or muon, large missing transverse
energy, and exactly four high-energy jets, at least one of which is tagged as
coming from a b quark. A likelihood is calculated using a matrix element method
with quasi-Monte Carlo integration taking into account finite detector
resolution and jet mass effects. The event likelihood is a function of m_t and
a parameter DJES to calibrate the jet energy scale /in situ/. Using a total of
1087 events, a value of m_t = 173.0 +/- 1.2 GeV/c^2 is measured. | hep-ex |
A Microsoft Word Font for Anti-Matter: One often wishes to quickly add a few overlined characters such as anti-B0 or
anti-neutrino to a Microsoft Word document. Underlined characters are
straightforward but overlined characters require equation editor which makes
small picture files. The font here allows one to directly add overlined English
and the most used overlined Greek characters to Microsoft Word documents on
Apple Macintosh computers. | hep-ex |
Precise Branching Ratio Measurements of the Decays D0-->pi- pi+ pi0 and
D0-->K- K+ pi0: Using 232 fb-1 of e+e- collision data recorded by the BaBar experiment, we
measure the ratios of three-body Cabibbo-suppressed decay rates of the D^0
meson relative to that of the Cabibbo-favored decay:
B(D0 --> pi- pi+ pi0)/ B(D0 --> K- pi+ pi0) = (10.59 +/- 0.06 +/-
0.13).10^{-2} and B(D0 --> K- K+ pi0)/ B(D0 --> K- pi+ pi0) = (2.37 +/- 0.03
+/- 0.04). 10^{-2}, where the errors are statistical and systematic
respectively. The precisions of these measurements are significantly better
than those of the current world average values.We note that the second result
differs significantly from the current world average value. Using the PDG-2006
value for D0 --> K- pi+ pi0 branching fraction, we obtain, B(D0 --> pi- pi+
pi0) = (1.493 +/- 0.008 +/- 0.018 +/- 0.053). 10^{-2}, B(D0 --> K- K+ pi0) =
(0.334 +/- 0.004 +/- 0.006 +/- 0.012). 10^{-2}, where the errors are
statistical, systematic, and due to the uncertainty of B(D0 --> K- pi+ pi0).
The average squared matrix elements for both of the singly Cabibbo-suppressed
decays are roughly a factor of sin^2 \theta_C smaller than that for the
Cabibbo-favored decay and are therefore, in contrast to the corresponding
two-body modes, consistent with the naive expectations. | hep-ex |
Sleuth: A Quasi-Model-Independent Search Strategy for New Physics: How can we search for new physics when we only vaguely know what it should
look like? How can we perform an unbiased yet data-driven search? If we see
apparently anomalous events in our data, how can we quantify their
"interestingness" a posteriori? We present an analysis strategy (Sleuth) that
simultaneously addresses each of these questions, and we demonstrate its
application to over thirty exclusive final states in data collected by D0 in
Run I of the Fermilab Tevatron. | hep-ex |
Numerical Implementation of lepton-nucleus interactions and its effect
on neutrino oscillation analysis: We discuss the implementation of the nuclear model based on realistic nuclear
spectral functions in the GENIE neutrino interaction generator. Besides
improving on the Fermi gas description of the nuclear ground state, our scheme
involves a new prescription for $Q^2$ selection, meant to efficiently enforce
energy momentum conservation. The results of our simulations, validated through
comparison to electron scattering data, have been obtained for a variety of
target nuclei, ranging from carbon to argon, and cover the kinematical region
in which quasi elastic scattering is the dominant reaction mechanism. We also
analyse the influence of the adopted nuclear model on the determination of
neutrino oscillation parameters. | hep-ex |
Observation of $D^0\to ρ^0γ$ and search for $CP$ violation in
radiative charm decays: We report the first observation of the radiative charm decay $D^0 \to \rho^0
\gamma$ and the first search for $CP$ violation in decays $D^0 \to \rho^0
\gamma$, $\phi\gamma$, and $\overline{K}{}^{*0} \gamma$, using a data sample of
943 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy
$e^+e^-$ collider. The branching fraction is measured to be $\mathcal{B}(D^0
\to \rho^0 \gamma)=(1.77 \pm 0.30 \pm 0.07) \times 10^{-5}$, where the first
uncertainty is statistical and the second is systematic. The obtained $CP$
asymmetries, $\mathcal{A}_{CP}(D^0 \to \rho^0 \gamma)=+0.056 \pm 0.152 \pm
0.006$, $\mathcal{A}_{CP}(D^0 \to \phi \gamma)=-0.094 \pm 0.066 \pm 0.001$, and
$\mathcal{A}_{CP}(D^0 \to \overline{K}{}^{*0} \gamma)=-0.003 \pm 0.020 \pm
0.000$, are consistent with no $CP$ violation. We also present an improved
measurement of the branching fractions $\mathcal{B}(D^0 \to \phi \gamma)=(2.76
\pm 0.19 \pm 0.10) \times 10^{-5}$ and $\mathcal{B}(D^0 \to \overline{K}{}^{*0}
\gamma)=(4.66 \pm 0.21 \pm 0.21) \times 10^{-4}$. | hep-ex |
Future Atmospheric Neutrino Detectors: Future experiments focusing on atmospheric neutrino detection are reviewed.
One of the main goals of these experiments is the detection of an unambiguous
oscillation pattern (nu_mu reappearance) to prove the oscillation hypothesis.
Further goals include the discrimination of nu_mu - nu_tau and nu_mu -
nu_sterile oscillations, and the detection of a potential small nu_mu - nu_e
contribution. The search for matter effects in three or more flavour
oscillations can be used to constrain hybrid oscillation models and potentially
measure the sign of delta m^2. The detectors and measurement techniques
proposed to achieve these goals are described, and their physics reach is
discussed. | hep-ex |
Higgs Searches at LEP and at the Tevatron: After years of efforts to push the LEP performance to, and indeed beyond, the
limits of what had been believed possible, hints of signal of a Higgs boson at
115GeV/c2 appeared in June 2000, were confirmed in September, and confirmed
again in November. Spending an additional six-month period with LEP would have
given the unambiguous opportunity of a fundamental discovery. Instead, this
possibilty was handed over to the Tevatron, for which at least si more years
will be needed to confirm the existence of a Higgs boson around 115GeV/c2. The
upgrades performed at LEP and needed at the Tevatron, together with the physics
outcomes, are briefly mentioned in turn. | hep-ex |
Limits on Interactions between Weakly Interacting Massive Particles and
Nucleons Obtained with NaI(Tl) crystal Detectors: Limits on the cross section for weakly interacting massive particles (WIMPs)
scattering off nucleons in the NaI(Tl) detectors at the Yangyang Underground
Laboratory are obtained with a 2967.4 kg*day data exposure. Nuclei recoiling
are identified by the pulse shape of scintillating photon signals. Data are
consistent with no nuclear recoil hypothesis, and 90% confidence level upper
limits are set. These limits partially exclude the DAMA/LIBRA region of
WIMP-sodium interaction with the same NaI(Tl) target detector. This 90%
confidence level upper limit on WIMP-nucleon spin-independent cross section is
3.26*10^-4 pb for a WIMP mass at 10 GeV/c^2. | hep-ex |
Measurements of the top quark mass and decay width with the D0 detector: The top quark discovery in 1995 at Fermilab is one of the major proofs of the
standard model (SM). Due to its unique place in SM, the top quark is an
important particle for testing the theory and probing for new physics. This
article presents most recent measurements of top quark properties from the D0
detector. In particular, the measurement of the top quark mass, the top antitop
mass difference and the top quark decay width. | hep-ex |
Taiwan Axion Search Experiment with Haloscope: CD102 Analysis Details: This paper presents the analysis of the data acquired during the first
physics run of the Taiwan Axion Search Experiment with Haloscope (TASEH), a
search for axions using a microwave cavity at frequencies between 4.70750 and
4.79815 GHz. The data were collected from October 13, 2021 to November 15,
2021, and are referred to as the CD102 data. The analysis of the TASEH CD102
data excludes models with the axion-two-photon coupling $|g_{a\gamma\gamma}|
\gtrsim 8.2\times 10^{-14}$ GeV$^{-1}$, a factor of eleven above the benchmark
KSVZ model for the mass range 19.4687 < ma < 19.8436 $\mu$eV. | hep-ex |
Observation of Single Top Quark Production at D0: This paper presents the observation of the electroweak production of single
top quarks in the D0 detector at the Fermilab Tevatron Collider at a
center-of-mass energy of 1.96 TeV. Events containing an isolated electron or
muon and missing transverse energy, together with jets originating from the
fragmentation of b quarks are used to measure a cross section for single top
quark production of sigma(ppbar -> tb + X, tqb + X) = 3.94 +- 0.88 pb. The
probability to measure a cross section at this value or higher in the absence
of signal is 2.5X10^-7, corresponding to a 5.0 standard deviation significance. | hep-ex |
Search for the rare decays $J/ψ\to D_s^-ρ^+$ and $J/ψ\to
\overline{D}{}^0\overline{K}{}^{\ast0}$: A search for the rare decays of $J/\psi \to D_s^-\rho^+ + c.c.$ and $J/\psi
\to \overline{D}{}^0\overline{K}{}^{\ast0} + c.c.$ is performed with a data
sample of 225.3 million $J/\psi$ events collected with the BESIII detector. No
evident signal is observed. Upper limits on the branching fractions are
determined to be $\mathcal{B}(J/\psi \to D_s^-\rho^+ + c.c.) < 1.3 \times
10^{-5}$ and $\mathcal{B}(J/\psi \to \overline{D}{}^0\overline{K}{}^{\ast0} +
c.c.) < 2.5 \times 10^{-6}$ at the $90\%$ confidence level. | hep-ex |
The onset of the anomalous J/psi suppression in Pb-Pb collisions at the
CERN SPS: The J/psi suppression observed by the NA50 experiment is one of the most
striking signatures for quark gluon plasma formation in Pb-Pb collisions at 158
AGeV. The J/psi production has been studied as a function of the centrality of
the collision estimated via the forward energy EZDC released in a zero degree
calorimeter (ZDC). The study of the correlation between the number of
participant nucleons in the collisions, Npart, and EZDC allows to check whether
the J/psi suppression pattern vs. EZDC is compatible with a sudden J/psi
suppression mechanism expressed as a function of Npart. | hep-ex |
RFQD - a Decelerating Radio Frequency Quadrupole for the CERN Antiproton
Facility: The RFQD is designed to decelerate antiprotons of momentum 100 MeV/c (kinetic
energy 5.33MeV)down to a kinetic energy variable between ~10 keV and 120 keV.
Inside the RFQ body, at ground potential, the rf structure of the four-rod type
is mounted on insulating supports. It can be biased between plus/minus 60 kV dc
to achieve the continuous adjustment of output energy required by the ASACUSA
experiment at the CERN Antiproton Decelerator AD. The different parts of the
system are described and the present status reported. | hep-ex |
Evidence for Narrow S=+1 Baryon Resonance in Photo-production from
Neutron: The gamma n -> K+ K- n reaction on 12C has been studied by measuring both K+
and K- at forward angles. A sharp baryon resonance peak was observed at 1.54 +-
0.01 GeV with a width smaller than 25 MeV and a Gaussian significance of 4.6
sigma. The strangeness quantum number (S) of the baryon resonance is +1. It can
be interpreted as a molecular meson-baryon resonance or alternatively as an
exotic 5-quark state (uudd{s_bar}) that decays into a K+ and a neutron. The
resonance is consistent with the lowest member of an anti-decuplet of baryons
predicted by the chiral soliton model. | hep-ex |
Study of the rare $B_s^0$ and $B^0$ decays into the
$π^+π^-μ^+μ^-$ final state: A search for the rare decays $B_s^0 \to \pi^+\pi^-\mu^+\mu^-$ and $B^0 \to
\pi^+\pi^-\mu^+\mu^-$ is performed in a data set corresponding to an integrated
luminosity of 3.0 fb$^{-1}$ collected by the LHCb detector in proton-proton
collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with
pion pairs that have invariant mass in the range 0.5-1.3 GeV/$c^2$ and with
muon pairs that do not originate from a resonance are considered. The first
observation of the decay $B_s^0 \to \pi^+\pi^-\mu^+\mu^-$ and the first
evidence of the decay $B^0 \to \pi^+\pi^-\mu^+\mu^-$ are obtained and the
branching fractions, restricted to the dipion-mass range considered, are
measured to be $\mathcal{B}(B_s^0 \to \pi^+\pi^-\mu^+\mu^-)=(8.6\pm 1.5\,({\rm
stat}) \pm 0.7\,({\rm syst})\pm 0.7\,({\rm norm}))\times 10^{-8}$ and
$\mathcal{B}(B^0 \to \pi^+\pi^-\mu^+\mu^-)=(2.11\pm 0.51\,({\rm stat}) \pm
0.15\,({\rm syst})\pm 0.16\,({\rm norm}) )\times 10^{-8}$, where the third
uncertainty is due to the branching fraction of the decay $B^0\to J/\psi(\to
\mu^+\mu^-)K^*(890)^0(\to K^+\pi^-)$, used as a normalisation. | hep-ex |
Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN: We discuss aspects of antihydrogen studies, that relate to particle physics
ideas and techniques, within the context of the ALPHA experiment at CERN's
Antiproton Decelerator facility. We review the fundamental physics motivations
for antihydrogen studies, and their potential physics reach. We argue that
initial spectroscopy measurements, once antihydrogen is trapped, could provide
competitive tests of CPT, possibly probing physics at the Planck Scale. We
discuss some of the particle detection techniques used in ALPHA. Preliminary
results from commissioning studies of a partial system of the ALPHA Si vertex
detector are presented, the results of which highlight the power of
annihilation vertex detection capability in antihydrogen studies. | hep-ex |
N* and Meson Resonances in J/psi decays: Over sixty million J/psi events have been collected by the BES Collaboration
at the Beijing Electron-Positron Collider (BEPC). J/psi decays provide an
excellent place for studying excited nucleons and hyperons -- N*, $\Lambda^*$,
$\Sigma^*$ and $\Xi^*$ resonances, as well as meson resonances, including
possible glueballs and hybrids. Physics objectives, recent results and future
prospects of light hadron spectroscopy at BEPC are presented. | hep-ex |
Search for b --> u Transitions in B^{+-} --> [K^{-+} pi^{+-} pi0]_D
K^{+-} Decays: We present a study of the decays B^{+-} --> D K^{+-} with D mesons
reconstructed in the K+pi-pi0 or K-pi+pi0 final states, where D indicates a D0
or a anti-D0 meson. Using a sample of 474 million BBbar pairs collected with
the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC we
obtain R^{+} = (5^{+12}_{-10}(stat) ^{+2}_{-4}(syst))\times10^{-3} and R^{-} =
(12^{+12}_{-10}(stat) ^{+3}_{-5}(syst))\times10^{-3}, from which we extract the
upper limits at 90% probability: R^+<23\times10^{-3} and R^-<29\times10^{-3}.
Using these measurements, we obtain an upper limit for the ratio rB of the
magnitudes of the b --> u and b --> c amplitudes r_B<0.13 at 90% probability. | hep-ex |
First measurement of the cross section for $ν_μ$ and $\barν_μ$
induced single charged pion production on argon using ArgoNeuT: We report on the first cross section measurement of charged-current single
charged pion production by neutrinos and antineutrinos on argon. This analysis
was performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab.
The measurements are presented as functions of muon momentum, muon angle, pion
angle, and angle between muon and pion. The flux-averaged cross sections are
measured to be $2.7\pm0.5(stat)\pm0.5(syst) \times 10^{-37}
\textrm{cm}^{2}/\textrm{Ar}$ for neutrinos at a mean energy of 9.6 GeV and
$8.4\pm0.9(stat)^{+1.0}_{-0.8}(syst) \times 10^{-38}
\textrm{cm}^{2}/\textrm{Ar}$ for antineutrinos at a mean energy of 3.6 GeV with
the charged pion momentum above 100 MeV/$c$. The results are compared with
several model predictions. | hep-ex |
Short-Range and Long-Range Correlations in DIS at HERA: Correlations in deep-inelastic scattering at HERA are investigated in order
to test perturbative QCD and quark fragmentation universality. Two-particle
correlations at small angular separations are measured in the Breit frame and
compared to e+e- collisions. Also presented are the correlations between the
current and target regions of the Breit frame. | hep-ex |
The Double Chooz reactor neutrino experiment: The Double Chooz reactor neutrino experiment will be the next detector to
search for a non vanishing theta13 mixing angle with unprecedented sensitivity,
which might open the way to unveiling CP violation in the leptonic sector. The
measurement of this angle will be based in a precise comparison of the
antineutrino spectrum at two identical detectors located at different distances
from the Chooz nuclear reactor cores in France. Double Chooz is particularly
attractive because of its capability to measure sin2(2theta13) to 3 sigmas if
sin2(2theta13) > 0.05 or to exclude sin2(2theta13) down to 0.03 at 90% C.L. for
Dm2 = 2.5 x 10-3 eV2 in three years of data taking with both detectors. The
construction of the far detector starts in 2008 and the first neutrino results
are expected in 2009. The current status of the experiment, its physics
potential and design and expected performance of the detector are reviewed. | hep-ex |
Search for new phenomena with the monojet and missing transverse
momentum signature using the ATLAS detector in sqrt(s) = 7 TeV proton-proton
collisions: A search for new phenomena in events featuring a high energy jet and large
missing transverse momentum in proton-proton collisions at sqrt(s) = 7 TeV is
presented using a dataset corresponding to an integrated luminosity of 33 pb^-1
recorded with the ATLAS detector at the Large Hadron Collider. The number of
observed events is consistent with the Standard Model prediction and this
result is interpreted in terms of limits on a model of Large Extra Dimensions. | hep-ex |
Observation of B- to pbar Lambda D0 at Belle: We study B- meson decays to pbar Lambda D(*)0 final states using a sample of
657 * 10^6 B Bbar events collected at the Upsilon(4S) resonance with the Belle
detector at the KEKB asymmetric-energy e+ e- collider. The observed branching
fraction for B- to pbar Lambda D0 is (1.43^ +0.28_-0.25 +- 0.18)*10^-5. with a
significance of 8.1 standard deviations, where the uncertainties are
statistical and systematic, respectively. Most of the signal events have the
pbarLambda mass peaking near threshold. No significant signal is observed for
B- to pbar Lambda D*0 and the corresponding upper limit on the branching
fraction is 4.8 * 10^-5 at the 90% confidence level. | hep-ex |
Key4hep: Progress Report on Integrations: Detector studies for future experiments rely on advanced software tools to
estimate performance and optimize their design and technology choices. The
Key4hep project provides a flexible turnkey solution for the full experiment
life-cycle based on established community tools such as ROOT, Geant4, DD4hep,
Gaudi, podio and spack. Members of the CEPC, CLIC, EIC, FCC, and ILC
communities have joined to develop this framework and have merged, or are in
the progress of merging, their respective software environments into the
Key4hep stack. These proceedings will give an overview over the recent progress
in the Key4hep project: covering the developments towards adaptation of
state-of-the-art tools for simulation (DD4hep, Gaussino), track and calorimeter
reconstruction (ACTS, CLUE), particle flow (PandoraPFA), analysis via
RDataFrame, and visualization with Phoenix, as well as tools for testing and
validation. | hep-ex |
On the possibility to use ATLAS and CMS detectors for neutrino physics: Energetic primary cosmic rays entering the Earth's atmosphere generate flux
of secondary particles including neutrinos. Muon neutrinos passed through the
Earth and produced muons via the charged current reaction can be registered by
experimental setups intended for the measurements with colliding beams. Due to
large geometrical size and advanced muon detecting system such detectors as
ATLAS and CMS on LHC have chance to contribute also into the neutrino physics.
The estimation of possible rates of up-going muons produced by neutrinos is
given. | hep-ex |
Observation of single top quark production in association with a Z boson
in proton-proton collisions at $\sqrt{s} =$ 13 TeV: The observation of single top quark production in association with a Z boson
and a quark (tZq) is reported. Events from proton-proton collisions at a
center-of-mass energy of 13 TeV containing three charged leptons (either
electrons or muons) and at least two jets are analyzed. The data were collected
with the CMS detector in 2016 and 2017, and correspond to an integrated
luminosity of 77.4 fb$^{-1}$. The increased integrated luminosity, a
multivariate lepton identification, and a redesigned analysis strategy improve
significantly the sensitivity of the analysis compared to previous searches for
tZq production. The tZq signal is observed with a significance well over five
standard deviations. The measured tZq production cross section is $\sigma$(pp
$\to$ tZq $\to$ t$\ell^{+} \ell^{-}$q) = 111 $\pm$ 13 (stat) $ _{-9}^{+11}$
(syst) fb, for dilepton invariant masses above 30 GeV, in agreement with the
standard model expectation. | hep-ex |
Search for B+ -> l+ nu gamma decays with hadronic tagging using the full
Belle data sample: We search for the decay B+ -> l+ nu gamma with l+ = e+ or mu+ using the full
Belle data set of 772 x 10^6 BBbar pairs, collected at the Y(4S) resonance with
the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct
one B meson in a hadronic decay mode and search for the B+ -> l+ nu gamma decay
in the remainder of the event. We observe no significant signal within the
phase space of E_gamma^sig > 1 GeV and obtain upper limits of BR(B+ -> e+ nu
gamma) < 6.1 x 10^-6, BR(B+ -> mu+ nu gamma) < 3.4 x 10^-6, and BR(B+ -> l+ nu
gamma) < 3.5 x 10^-6 at 90 % credibility level. | hep-ex |
Standard Model Physics Results from LEP2: At LEP2 many Standard Model predictions are tested up to centre-of-mass
energies of 209 GeV. Fermion pair production cross sections and asymmetries
agree well with the theoretical expectation over the entire energy range. The
measurements are used to determine the gamma/Z interference and to search for
contact interactions up to 20 TeV. The cross sections for single-W, ZZ and W+W-
production agree well with the expectations. The branching fractions of the W
boson into hadrons and leptons are determined as well as the CKM matrix element
|V_{cs}|. Precise measurements of the W mass and width are presented yielding
MW=80.427+-0.046 GeV and GammaW=2.12=_0.11 GeV. All electroweak data are very
consistent with the Standard Model predictions. In a combined fit using the
recent value of Delta alpha_{had}^(5)(s) the mass of the Higgs boson is
constrained to MH=88^{+60}_{-37} GeV. | hep-ex |
Transition to the region of central collisions and critical phenomena: The experimental results on the relation between the processes of total
disintegration of nuclei (or the cases with central collisions) and the
critical phenomena which can occur in the region of high degree of nuclear
disintegration or of collision centrality are discussed. | hep-ex |
Enhanced NeUtrino BEams from kaon Tagging (ENUBET): ENUBET aims at demonstrating the feasibility of a "monitored" neutrino beam,
in which the absolute normalization of the neutrino flux can be constrained at
the 1% level. The $\nu_e$ flux is determined by monitoring large-angle $e^+$
from $K_{e3}$ decays in a 40 m long instrumented decay tunnel. The $\nu_\mu$
flux is provided by muons produced by decays of $K$ and $\pi$. Being a narrow
band beam ($p=8.5$ GeV/$c$ $\pm$ 10%), the transverse position of the
interaction at the detector can be exploited to determine a priori the neutrino
energy spectrum without relying on the final state reconstruction ("narrow band
off-axis technique"). Lepton monitoring and narrow band off-axis energy
reconstruction can be implemented in a single facility based on standard
accelerator technologies for a new generation of high precision $\nu_e$ and
$\nu_\mu$ cross section measurements at the GeV scale and for precision
searches of physics beyond the standard 3$\nu$ paradigm. In 2019-2022 ENUBET
has devised the first end-to-end simulation of the facility and demonstrated
that the precision goals can be achieved in $\sim$ 3 years of data taking
employing neutrino detectors of moderate mass (ICARUS at FNAL, ProtoDUNE at
CERN). The technology of a monitored beam has been proven to be feasible and
cost-effective, and the complexity does not exceed significantly the one of a
conventional short-baseline beam. The Snowmass 2021 DPF Community Planning
Exercise is thus timely for the consideration of monitored neutrino beams
hosting the next generation of cross section experiments. The ENUBET results
will play an important role in the systematic reduction programme of future
long baseline experiments, thus enhancing the physics reach of DUNE and
Hyper-Kamiokande. In this document, we summarize the ENUBET design, physics
performance and opportunities for its implementation in a timescale comparable
with DUNE. | hep-ex |
Rare decay searches at CDF: In the last decade the CDF experiment at the Tevatron clearly demonstrated
that it is possible to study extensively heavy flavour physics in hadron
collisions and achieve remarkable results, competitive and complementary to
$B$-factories. In this paper we report on the indirect searches for physics
beyond the standard model via measurements of rare $b$-hadron decays. The final
limits, based on the analysis of the full CDF data set, on the branching
fraction of the $B^0_{(s)}$ decay into a pair of muons are presented and
discussed. Moreover we review the latest measurements, with 6.8 fb$^{-1}$ of
collected data, of the total and differential branching fractions and angular
observables of rare $b$-hadron decays proceeding via the flavour-changing
neutral-current process $b \rightarrow s \mu^+ \mu^-$. PACS numbers: 13.20.He,
13.30.-a, 12.15.Mn | hep-ex |
Search for neutral Higgs bosons in multi-$b$-jet events in $p\bar{p}$
collisions at $\sqrt{s} = 1.96$ TeV: Data recorded by the D0 experiment at the Fermilab Tevatron Collider are
analyzed to search for neutral Higgs bosons produced in association with $b$
quarks. This production mode can be enhanced in the minimal supersymmetric
standard model (MSSM). The search is performed in the three $b$ quark channel
using multijet triggered events corresponding to an integrated luminosity of $1
\mathrm{fb}^{-1}$. No statistically significant excess of events with respect
to the predicted background is observed and limits are set in the MSSM
parameter space. | hep-ex |
Single Phonon Detection for Dark Matter via Quantum Evaporation and
Sensing of $^3$Helium: Dark matter is five times more abundant than ordinary visible matter in our
Universe. While laboratory searches hunting for dark matter have traditionally
focused on the electroweak scale, theories of low mass hidden sectors motivate
new detection techniques. Extending these searches to lower mass ranges, well
below 1 GeV/c$^2$, poses new challenges as rare interactions with standard
model matter transfer progressively less energy to electrons and nuclei in
detectors. Here, we propose an approach based on phonon-assisted quantum
evaporation combined with quantum sensors for detection of desorption events
via tracking of spin coherence. The intent of our proposed dark matter sensors
is to extend the parameter space to energy transfers in rare interactions to as
low as a few meV for detection of dark matter particles in the keV/c$^2$ mass
range. | hep-ex |
Measurements of differential $t\bar{t}$ production cross sections at CMS: An overview of recent measurements of differential top quark pair production
cross sections performed by the CMS experiment at the LHC is presented.
Measurements at different proton-proton center-of-mass energies are available
using the dilepton, lepton+jets, and all-jets decay channels of the top quark.
In addition to the measurements of parton-level top quarks, many measurements
at particle level in an experimental accessible phase space are now available.
For these results the dependence on theoretical extrapolations is reduced. A
common observation of all measurements is a softer transverse momentum of the
top quark than predicted by state of the art standard model calculations.
However, new calculations with NNLO QCD and NLO electro-weak precision show an
improved agreement. | hep-ex |
Measurement of the high-energy all-flavor neutrino-nucleon cross section
with IceCube: The flux of high-energy neutrinos passing through the Earth is attenuated due
to their interactions with matter. The interaction rate is modulated by the
neutrino interaction cross section and affects the flux arriving at the IceCube
Neutrino Observatory, a cubic-kilometer neutrino detector embedded in the
Antarctic ice sheet. We present a measurement of the neutrino cross section
between 60 TeV and 10 PeV using the high-energy starting events (HESE) sample
from IceCube with 7.5 years of data. The result is binned in neutrino energy
and obtained using both Bayesian and frequentist statistics. We find it
compatible with predictions from the Standard Model. Flavor information is
explicitly included through updated morphology classifiers, proxies for the the
three neutrino flavors. This is the first such measurement to use the three
morphologies as observables and the first to account for neutrinos from tau
decay. | hep-ex |
Heavy Quark Production and Decay: t, b, and onia: This paper summarizes a variety of recent results on heavy quark production
and decay. Considerable progress has been made by CDF and D0 in measuring top
quark production and decay properties. The top quark mass been measured with an
uncertainty that is less than 3%, a relative precision that is better than has
been achieved for other quarks. Measurements of the top production and decay
properties are consistent with the Standard Model predictions, but are
generally limited in precision by the small number of top quark events in the
present data samples. ALEPH and CLEO have measured the branching ratio for the
flavor changing neutral current decay b->s gamma and find good agreement with
the Standard Model. Measurements of b-quark production cross sections in ppbar
collisions by CDF and D0 and in ep collisions by H1 continue to show
discrepancies between theory and experiment. CDF and DELPHI have measured the
b-quark fragmentation fractions with better accuracy than previous
measurements. Finally, measurements of charmonium production by D0, E771, and
L3 are consistent with predictions of the color octet model. | hep-ex |
Search for pair production of heavy vector-like quarks decaying into
high-$p_T$ $W$ bosons and top quarks in the lepton-plus-jets final state in
$pp$ collisions at $\sqrt{s}$=13 TeV with the ATLAS detector: A search is presented for the pair production of heavy vector-like $B$
quarks, primarily targeting $B$ quark decays into a $W$ boson and a top quark.
The search is based on $36.1$ $fb^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13
TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron
Collider. Data are analysed in the lepton-plus-jets final state, characterised
by a high-transverse-momentum isolated electron or muon, large missing
transverse momentum, and multiple jets, of which at least one is $b$-tagged. No
significant deviation from the Standard Model expectation is observed. The 95%
confidence level lower limit on the $B$ mass is 1350 GeV assuming a 100%
branching ratio to $Wt$. In the SU(2) singlet scenario, the lower mass limit is
1170 GeV. This search is also sensitive to a heavy vector-like $B$ quark
decaying into other final states ($Zb$ and $Hb$) and thus mass limits on $B$
production are set as a function of the decay branching ratios. The 100%
branching ratio limits are found to be also applicable to heavy vector-like $X$
production, with charge $+$5/3, that decay into $Wt$. | hep-ex |
Rare decay searches at CDF: In the last decade the CDF experiment at the Tevatron clearly demonstrated
that it is possible to study extensively heavy flavour physics in hadron
collisions and achieve remarkable results, competitive and complementary to
$B$-factories. In this paper we report on the indirect searches for physics
beyond the standard model via measurements of rare $b$-hadron decays. The final
limits, based on the analysis of the full CDF data set, on the branching
fraction of the $B^0_{(s)}$ decay into a pair of muons are presented and
discussed. Moreover we review the latest measurements, with 6.8 fb$^{-1}$ of
collected data, of the total and differential branching fractions and angular
observables of rare $b$-hadron decays proceeding via the flavour-changing
neutral-current process $b \rightarrow s \mu^+ \mu^-$. PACS numbers: 13.20.He,
13.30.-a, 12.15.Mn | hep-ex |
Confirmation of a charged charmoniumlike state $Z_c(3885)^{\mp}$ in
$e^+e^-\toπ^{\pm}(D\bar{D}^*)^\mp$ with double $D$ tag: We present a study of the process $e^+e^-\to\pi^{\pm}(D\bar{D}^*)^{\mp}$
using data samples of 1092~pb$^{-1}$ at $\sqrt{s}=4.23$~GeV and 826~pb$^{-1}$
at $\sqrt{s}=4.26$~GeV collected with the BESIII detector at the BEPCII storage
ring. With full reconstruction of the $D$ meson pair and the bachelor
$\pi^{\pm}$ in the final state, we confirm the existence of the charged
structure $Z_c(3885)^{\mp}$ in the $(D\bar{D}^*)^{\mp}$ system in the two
isospin processes $e^+e^-\to\pi^+D^0D^{*-}$ and $e^+e^-\to\pi^+D^-D^{*0}$. By
performing a simultaneous fit, the statistical significance of $Zc(3885)^{\mp}$
signal is determined to be greater than 10$\sigma$, and its pole mass and width
are measured to be
$M_{\rm{pole}}$=(3881.7$\pm$1.6(stat.)$\pm$1.6(syst.))~MeV/$c^2$ and
$\Gamma_{\rm{pole}}$=(26.6$\pm$2.0(stat.)$\pm$2.1(syst.))~MeV, respectively.
The Born cross section times the $(D\bar{D}^*)^{\mp}$ branching fraction
($\sigma(e^+e^-\to\pi^{\pm}Z_{c}(3885)^{\mp}) \times
Br(Z_{c}(3885)^{\mp}\to(D\bar{D}^*)^{\mp})$) is measured to be
$(141.6\pm7.9(\text{stat.})\pm12.3(\text{syst.}))~\text{pb}$ at
$\sqrt{s}=4.23$~GeV and
$(108.4\pm6.9(\text{stat.})\pm8.8(\text{syst.}))~\text{pb}$ at
$\sqrt{s}=4.26$~GeV. The polar angular distribution of the
$\pi^{\pm}$-$Z_c(3885)^{\mp}$ system is consistent with the expectation of a
quantum number assignment of $J^P=1^+$ for $Z_c(3885)^{\mp}$. | hep-ex |
Probing the quantum interference between singly and doubly resonant
top-quark production in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS
detector: This Letter presents a normalized differential cross-section measurement in a
fiducial phase-space region where interference effects between top-quark pair
production and associated production of a single top quark with a $W$ boson and
a $b$-quark are significant. Events with exactly two leptons ($ee$, $\mu\mu$,
or $e\mu$) and two $b$-tagged jets that satisfy a multi-particle invariant mass
requirement are selected from $36.1$ fb$^{-1}$ of proton-proton collision data
taken at $\sqrt{s}=13$ TeV with the ATLAS detector at the LHC in 2015 and 2016.
The results are compared with predictions from simulations using various
strategies for the interference. The standard prescriptions for interference
modeling are significantly different from each other but are within $2\sigma$
of the data. State-of-the-art predictions that naturally incorporate
interference effects provide the best description of the data in the measured
region of phase space most sensitive to these effects. These results provide an
important constraint on interference models and will guide future model
development and tuning. | hep-ex |
Measurement of the top pair invariant mass distribution at 7 TeV and
search for new physics: An overview of searches for new physics in the ttbar sample from the CMS
Collaboration is presented with data collected at the Large Hadron Collider at
sqrt(s) = 7 TeV. There are several searches presented, including same-sign
dilepton signatures, semileptonic signatures, and all-hadronic signatures, the
latter of which uses advanced jet reconstruction techniques. | hep-ex |
Observation of the phi to pi+pi-pi+pi- Decay: Using 11.6 pb^{-1} of data collected in the energy range 0.984--1.06 GeV by
CMD-2 at VEPP-2M, the cross section of the reaction e+e- to pi+pi-pi+pi- has
been studied. For the first time an interference pattern was observed in the
energy dependence of the cross section near the phi meson. The branching ratio
of the phi to pi+pi-pi+pi- decay double suppressed by the G-parity and OZI rule
is measured Br(phi to pi+pi-pi+pi-) = (3.93 +- 1.74 +- 2.14) \cdot 10^{-6}. The
upper limits have been placed for the decays phi to pi+pi-pi+pi-pi0 and phi to
eta pi+pi-
Br(phi to pi+pi-pi+pi-pi0) < 4.6 \cdot 10^{-6} 90% CL,
Br(phi to eta pi+pi-) < 1.8 \cdot 10^{-5} 90% CL. | hep-ex |
Detection of Cascades induced by Atmospheric Neutrinos in the 79-string
IceCube Detector: Neutrino production and oscillation physics can be studied by utilizing the
very high flux of atmospheric neutrinos observed with IceCube. In a Cherenkov
medium such as ice, atmospheric muon neutrino interactions create tracks while
cascades (showers) are produced by atmospheric electron neutrinos and by
neutral current interactions of all flavors. We present the first detection of
atmospheric neutrino-induced cascades at energies between 30 GeV and 10 TeV
using the DeepCore array of the IceCube detector. Using 281 days of data, 1029
events are observed with 59% predicted to be cascades. | hep-ex |
Search for supersymmetry, extra dimensions and exotic phenomena at LEP: The latest results on searches for supersymmetry, extra dimensions and exotic
phenomena from the LEP collaborations are presented. No significant signal-like
excess is observed in the data. The results are interpreted in various models
and robust constraints are placed. | hep-ex |
Rapidity-Rank Structure of p pbar Pairs in Hadronic Z0 Decays: The rapidity-rank structure of p pbar pairs is used to analyze the mechanism
of baryon production in hadronic Z0 decay. The relative occurrence of the
rapidity-ordered configuration p M pbar, where M is a meson, and that of p pbar
adjacent pairs is compared. The data are found to be consistent with
predictions from a mechanism producing adjacent-rank p pbar pairs, without
requiring `string-ordered' p M pbar configurations. An upper limit of 15% at
90% confidence is determined for the p M pbar contribution. | hep-ex |
Search for dark matter-nucleon interactions via Migdal effect with
DarkSide-50: Dark matter elastic scattering off nuclei can result in the excitation and
ionization of the recoiling atom through the so-called Migdal effect. The
energy deposition from the ionization electron adds to the energy deposited by
the recoiling nuclear system and allows for the detection of interactions of
sub-GeV/c$^2$ mass dark matter. We present new constraints for sub-GeV/c$^2$
dark matter using the dual-phase liquid argon time projection chamber of the
DarkSide-50 experiment with an exposure of (12306 $\pm$ 184) kg d. The analysis
is based on the ionization signal alone and significantly enhances the
sensitivity of DarkSide-50, enabling sensitivity to dark matter with masses
down to 40 MeV/c$^2$. Furthermore, it sets the most stringent upper limit on
the spin independent dark matter nucleon cross section for masses below $3.6$
GeV/c$^2$. | hep-ex |
A New Measurement of eta_b(1S) From Upsilon(3S) Radiative Decay at CLEO: Using CLEO data, we report on the confirmation of the eta_b(1S0) ground state
of bottomonium in the radiative decay Upsilon(3S) -> gamma eta_b. We determine
its mass to be M(eta_b) = 9391.8 +- 6.6 +- 2.1 MeV, which corresponds to the
hyperfine splitting Delta M_hf(1S) = 68.5 +- 6.6 +- 2.0 MeV, and the branching
fraction B(Upsilon(3S) -> gamma eta_b) = (7.1 +- 1.8 +- 1.1) x 10^-4. These
results agree with those previously reported by BaBar. | hep-ex |
Supersymmetry searches at the Tevatron: CDF and D0 collaborations analyzed up to 200 pb-1 of the delivered data in
search for different supersymmetry signatures, so far with negative results. We
present results on searches for chargino and neutralino associated production,
squarks and gluinos, sbottom quarks, gauge mediated SUSY breaking and long
lived heavy particles. | hep-ex |
Precise Neutron Lifetime Measurement Using Pulsed Neutron Beams at
J-PARC: A neutron decays into a proton, an electron, and an anti-neutrino through the
beta-decay process. The decay lifetime ($\sim$880 s) is an important parameter
in the weak interaction. For example, the neutron lifetime is a parameter used
to determine the |$V_{\rm ud}$| parameter of the CKM quark mixing matrix. The
lifetime is also one of the input parameters for the Big Bang Nucleosynthesis,
which predicts light element synthesis in the early universe. However,
experimental measurements of the neutron lifetime today are significantly
different (8.4 s or 4.0$\sigma$) depending on the methods. One is a bottle
method measuring surviving neutron in the neutron storage bottle. The other is
a beam method measuring neutron beam flux and neutron decay rate in the
detector. There is a discussion that the discrepancy comes from unconsidered
systematic error or undetectable decay mode, such as dark decay. A new type of
beam experiment is performed at the BL05 MLF J-PARC. This experiment measured
neutron flux and decay rate simultaneously with a time projection chamber using
a pulsed neutron beam. We will present the world situation of neutron lifetime
and the latest results at J-PARC. | hep-ex |
Higgs and top physics reconstruction challenges and opportunities at
FCC-ee: The Higgs bosons and the top quark decay into rich and diverse final states,
containing both light and heavy quarks, gluons, photons as well as W and Z
bosons. This article reviews the challenges involved in reconstructing Higgs
and top events at the FCC-ee and identifies the areas where novel developments
are needed. The precise identification and reconstruction of these final states
at the FCC-ee rely on the capability of the detector to provide excellent
flavour tagging, jet energy and angular resolution, and global kinematic event
reconstruction. Excellent flavour tagging performance requires low-material
vertex and tracking detectors, and advanced machine learning techniques as
successfully employed in LHC experiments. In addition, the Z pole run will
provide abundant samples of heavy flavour partons that can be used for
calibration of the tagging algorithms. For the reconstruction of jets, leptons,
and missing energy, particle-flow algorithms are crucial to explore the full
potential of the highly granular tracking and calorimeter systems, and give
access to excellent energy-momentum resolution and precise identification of
heavy bosons in their hadronic decays. This enables, among many other key
elements, the reconstruction of Higgsstrahlung processes with leptonically and
hadronically decaying Z bosons, and an almost background-free identification of
top quark pair events. Exploiting the full available kinematic constraints
together with exclusive jet clustering algorithms will allow for the
optimisation of global event reconstruction with kinematic fitting techniques. | hep-ex |
Overview of the T2K long baseline neutrino oscillation experiment: Neutrino oscillations were discovered by atmospheric and solar neutrino
experiments, and have been confirmed by experiments using neutrinos from
accelerators and nuclear reactors. It has been found that there are large
mixing angles in the $\nu_e \to \nu_\mu$ and $\nu_\mu \to \nu_\tau$
oscillations. The third mixing angle $\theta_{13}$, which parameterizes the
mixing between the first and the third generation, is constrainted to be small
by the CHOOZ experiment result. The T2K experiment is a long baseline neutrino
oscillation experiment that uses intense neutrino beam produced at J-PARC and
Super-Kamiokande detector at 295 km as the far detector to measure
$\theta_{13}$ using $\nu_e$ appearance. In this talk, we will give an overview
of the experiment. | hep-ex |
Measurement of $b$-hadron pair production with the ATLAS detector in
proton-proton collisions at $\sqrt{s}=8$ TeV: A measurement of $b$-hadron pair production is presented, based on a data set
corresponding to an integrated luminosity of 11.4 fb$^{-1}$ of proton--proton
collisions recorded at $\sqrt{s}=8$ TeV with the ATLAS detector at the LHC.
Events are selected in which a $b$-hadron is reconstructed in a decay channel
containing $J/\psi \rightarrow \mu\mu$, and a second $b$-hadron is
reconstructed in a decay channel containing a muon. Results are presented in a
fiducial volume defined by kinematic requirements on three muons based on those
used in the analysis. The fiducial cross section is measured to be $17.7 \pm
0.1 ($stat.$) \pm 2.0 ($syst.$)$ nb. A number of normalised differential cross
sections are also measured, and compared to predictions from the Pythia8,
Herwig++, MadGraph5\_aMC@NLO+Pythia8 and Sherpa event generators, providing new
constraints on heavy flavour production. | hep-ex |
W$^+$W$^-$ boson pair production in proton-proton collisions at
$\sqrt{s} =$ 13 TeV: A measurement of the W$^+$W$^-$ boson pair production cross section in
proton-proton collisions at $\sqrt{s} =$ 13 TeV is presented. The data used in
this study are collected with the CMS detector at the CERN LHC and correspond
to an integrated luminosity of 35.9 fb$^{-1}$. The W$^+$W$^-$ candidate events
are selected by requiring two oppositely charged leptons (electrons or muons).
Two methods for reducing background contributions are employed. In the first
one, a sequence of requirements on kinematic quantities is applied allowing a
measurement of the total production cross section: 117.6 $\pm$ 6.8 pb, which
agrees well with the theoretical prediction. Fiducial cross sections are also
reported for events with zero or one jet, and the change in the zero-jet
fiducial cross section with the jet transverse momentum threshold is measured.
Normalized differential cross sections are reported within the fiducial region.
A second method for suppressing background contributions employs two random
forest classifiers. The analysis based on this method includes a measurement of
the total production cross section and also a measurement of the normalized jet
multiplicity distribution in W$^+$W$^-$ events. Finally, a dilepton invariant
mass distribution is used to probe for physics beyond the standard model in the
context of an effective field theory, and constraints on the presence of
dimension-6 operators are derived. | hep-ex |
Prospects for SUSY searches in CMS and ATLAS: We discuss how the CMS and ATLAS experiments are preparing for the analysis
of first LHC data with emphasis on the search for supersymmetry. We will show
the importance of the understanding of detector, trigger, reconstruction and
backgrounds, and we will present realistic estimates of the reach of CMS and
ATLAS. | hep-ex |
Search for squarks and gluinos in final states with jets and missing
transverse momentum at $\sqrt{s}=$ 13 TeV with the ATLAS detector: A search for squarks and gluinos in final states containing hadronic jets,
missing transverse momentum but no electrons or muons is presented. The data
were recorded in 2015 by the ATLAS experiment in $\sqrt{s}=$ 13 TeV
proton--proton collisions at the Large Hadron Collider. No excess above the
Standard Model background expectation was observed in 3.2 fb$^{-1}$ of analyzed
data. Results are interpreted within simplified models that assume R-parity is
conserved and the neutralino is the lightest supersymmetric particle. An
exclusion limit at the 95% confidence level on the mass of the gluino is set at
1.51 TeV for a simplified model incorporating only a gluino octet and the
lightest neutralino, assuming the lightest neutralino is massless. For a
simplified model involving the strong production of mass-degenerate first- and
second-generation squarks, squark masses below 1.03 TeV are excluded for a
massless lightest neutralino. These limits substantially extend the region of
supersymmetric parameter space excluded by previous measurements with the ATLAS
detector. | hep-ex |
Measurement of the inelastic proton-proton cross section at sqrt(s) = 7
TeV: A measurement is presented of the inelastic proton-proton cross section at a
centre-of-mass energy of sqrt(s) = 7 TeV. Using the CMS detector at the LHC,
the inelastic cross section is measured through two independent methods based
on information from (i) forward calorimetry (for pseudorapidity 3 < abs(eta) <
5), in collisions where at least one proton loses more than 5E-6 of its
longitudinal momentum, and (ii) the central tracker (abs(eta) < 2.4), in
collisions containing an interaction vertex with more than 1, 2, or 3 tracks
with transverse momenta pT > 200 MeV. The measurements cover a large fraction
of the inelastic cross section for particle production over about 9 units of
pseudorapidity and down to small transverse momenta. The results are compared
with those of other experiments, and with models used to describe high-energy
hadronic interactions. | hep-ex |
First Direct Bound on the Total Width of the Top Quark in ppbar
Collisions at sqrt(s) = 1.96 TeV: We present the first direct experimental bound on the total decay width of
the top quark using 955pb^-1 of the Tevatron's ppbar collisions recorded by the
Collider Detector at Fermilab. We identify 253 top-antitop pair candidate
events. The distribution of reconstructed top quark mass from these events is
fitted to templates representing different values of the top quark width. Using
a confidence interval based on likelihood ratio ordering, we extract an upper
limit at 95% C.L. of Gamma_t <13.1 GeV for an assumed top quark mass of 175
GeV/c^2. | hep-ex |
Neutrino Factory and Muon Collider R&D: European, Japanese, and US Neutrino Factory designs are presented. The main
R&D issues and associated R&D programs, future prospects, and the additional
issues that must be addressed to produce a viable Muon Collider design, are
discussed. | hep-ex |
Search for Theta(1540)^+ in exclusive proton-induced reaction p+C(N) \to
Theta^+ \bar{K}^0 + C(N) at the energy of 70 GeV: A search for narrow Theta(1540)^+, a candidate for pentaquark baryon with
positive strangeness, has been performed in an exclusive proton-induced
reaction p+C(N) \to Theta^+ \bar{K}^0 + C(N) on carbon nuclei or quasifree
nucleons at E_{beam}=70 GeV (sqrt{s} = 11.5 GeV) studying nK^+, pK_S and pK_L
decay channels of Theta(1540)^+ in four different final states of the Theta^+
\bar{K}^0 system. In order to assess the quality of the identification of the
final states with neutron or K_L we reconstructed Lambda(1520)\to nK_S and
phi\to K_LK_S decays in the calibration reactions p+C(N)\to Lambda(1520)K^+ +
C(N) and p+C(N)\to p\phi + C(N). We found no evidence for narrow pentaquark
peak in any of the studied final states and decay channels. Assuming that the
production characteristics of the Theta^+ \bar{K^0} system are not drastically
different from those of the Lambda(1520)K^+ and p\phi systems, we established
upper limits on the cross section ratios
sigma(Theta^+\bar{K}^0)/sigma(Lambda(1520)K^+) < 0.02 and
sigma(Theta^+\bar{K}^0)/sigma(p\phi) < 0.15 at 90% CL and a preliminary upper
limit for the forward hemisphere cross section sigma(Theta^+\bar{K}^0) < 30
nb/nucleon. | hep-ex |
Jet energy spectrum and substructure in $e^+e^-$ collisions at 91.2 GeV
with ALEPH Archived Data: The first measurements of energy spectra and substructure of anti-$k_{T}$
jets in hadronic $Z^0$ decays in $e^+e^-$ collisions are presented. The
archived $e^+e^-$ annihilation data at a center-of-mass energy of 91.2 GeV were
collected with the ALEPH detector at LEP in 1994. In addition to inclusive jet
and leading dijet energy spectra, various jet substructure observables are
analyzed as a function of jet energy which includes groomed and ungroomed jet
mass to jet energy ratios, groomed momentum sharing, and groomed jet radius.
The results are compared with perturbative QCD calculations and predictions
from the SHERPA, HERWIG v7.1.5, PYTHIA 6, PYTHIA 8, and PYQUEN event
generators. The jet energy spectra agree with perturbative QCD calculations
which include the treatment of logarithms of the jet radius and threshold
logarithms. None of the event generators give a fully satisfactory description
of the data. | hep-ex |
Perspectives for the detection and measurement of Supersymmetry in the
focus point region of mSUGRA models with the ATLAS detector at LHC: This paper discusses the ATLAS potential to study Supersymmetry for the
"Focus-Point" region of the parameter space of mSUGRA models. The potential to
discovery a deviation from Standard Model expectations with the first few
${fb}^{-1}$ of LHC data was studied using the parametrized simulation of the
ATLAS detector. Several signatures were considered, involving hard jets, large
missing energy, and either $b$-tagged jets, opposite-sign isolated electron or
muon pairs, or top quarks reconstructed exploiting their fully hadronic decays.
With only 1 ${fb}^{-1}$ of data each of these signatures may allow to observe
an excess of events over Standard Model expectation with a statistical
significance exceeding 5 standard deviations. An analytical expression was
derived for the shape of the distribution of the dilepton invariant mass
arising from the three-body leptonic decay of the neutralinos under the
hypothesis of heavy scalars, which is appropriate for the focus-point scenario.
The resulting function was used to fit the distribution of the dilepton
invariant mass obtained with simulated LHC data, and to extract the value of
two kinematic endpoints measuring the $\tilde \chi^0_2 - \tilde \chi^0_1$ and
the $\tilde \chi^0_3 - \tilde \chi^0_1$ mass differences. This information was
used to constrain the MSSM parameter space compatible with the data. | hep-ex |
Search for heavy Majorana neutrinos in e+/- e+/- plus jets and e+/-
mu+/- plus jets events in proton-proton collisions at sqrt(s) = 8 TeV: A search is performed for heavy Majorana neutrinos (N) decaying into a W
boson and a lepton using the CMS detector at the Large Hadron Collider. A
signature of two jets and either two same sign electrons or a same sign
electron-muon pair is searched for using 19.7 inverse femtobarns of data
collected during 2012 in proton-proton collisions at a centre-of-mass energy of
8 TeV. The data are found to be consistent with the expected standard model
(SM) background and, in the context of a Type-1 seesaw mechanism, upper limits
are set on the cross section times branching fraction for production of heavy
Majorana neutrinos in the mass range between 40 and 500 GeV. The results are
additionally interpreted as limits on the mixing between the heavy Majorana
neutrinos and the SM neutrinos. In the mass range considered, the upper limits
range between 0.00015 - 0.72 for |V[eN]|^2 and 6.6E-5 - 0.47 for |V[eN]
V*[muN]|^2 / ( |V[eN]|^2 + |V[muN]|^2 ), where V[lN] is the mixing element
describing the mixing of the heavy neutrino with the SM neutrino of flavour l.
These limits are the most restrictive direct limits for heavy Majorana neutrino
masses above 200 GeV. | hep-ex |
Enhancing the hunt for new phenomena in dijet final-states using anomaly
detection filters at the High-Luminosity Large Hadron Collider: In the realm of dijet searches in high-energy physics, a significant
challenge has emerged: with experiments producing more and more data, the
traditional methods of using analytic functions to describe dijet mass spectra
start to fail. To address this, we suggest the application of an anomaly
detection approach to eliminate less interesting background events based on
event final states. This method not only bypasses the limitations of
conventional background models but also significantly enhances our ability to
detect potential signals of new physics. Through simulations that mimic the
conditions of the upcoming High-Luminosity Large Hadron Collider, we
demonstrate the strength and efficiency of this approach in dealing with large
data volumes. The integration of unsupervised machine learning into our
experimental framework paves the way for a promising avenue to unveil hidden
physics discoveries within the overwhelming influx of data. | hep-ex |
Probing Gluons at the Spin Physics Detector: The Spin Physics Detector (SPD) at the Nuclotron based Ion Collider fAcility
(NICA) is a multi-purpose experiment designed to study nucleon spin structure
in the three dimensions. With capabilities to collide polarized protons and
deuterons with center of mass energy up to 27 GeV and luminosity up to $10^{32}
\rm cm^{-2} \ s^{-1}$ for protons (an order of magnitude less for deuterons),
the experiment will allow measurements of cross-sections and spin asymmetries
of hadronic processes sensitive to the unpolarized and various polarized
(helicity, Sivers, Boer-Mulders) gluon distributions inside the nucleons.
Results from the SPD will be complementary to the present high energy spin
experiments at the RHIC facility or future experiments like the EIC (at BNL)
and AFTER (at LHC). SPD will provide data in moderate and large Bjorken-x for
much improved global analyses of spin structures of the basic building blocks
of Nature. With polarized deuteron collisions, SPD will be the unique
laboratory for probing tensor polarized gluon distributions. In addition, there
are also possibilities of colliding other light nuclei like Carbon at reduced
collision energy and luminosity at the first stage of the experiment. | hep-ex |
Experimental and Phenomenological Investigations of the MiniBooNE
Anomaly: This thesis covers a range of experimental and theoretical efforts to
elucidate the origin of the $4.8\sigma$ MiniBooNE low energy excess (LEE). We
begin with the follow-up MicroBooNE experiment, which took data along the BNB
from 2016 to 2021. This thesis specifically presents MicroBooNE's search for
$\nu_e$ charged-current quasi-elastic (CCQE) interactions consistent with
two-body scattering. The two-body CCQE analysis uses a novel reconstruction
process, including a number of deep-learning-based algorithms, to isolate a
sample of $\nu_e$ CCQE interaction candidates with $75\%$ purity. The analysis
rules out an entirely $\nu_e$-based explanation of the MiniBooNE excess at the
$2.4\sigma$ confidence level. We next perform a combined fit of MicroBooNE and
MiniBooNE data to the popular $3+1$ model; even after the MicroBooNE results,
allowed regions in $\Delta m^2$-$\sin^2 2_{\theta_{\mu e}}$ parameter space
exist at the $3\sigma$ confidence level. This thesis also demonstrates that the
MicroBooNE data are consistent with a $\overline{\nu}_e$-based explanation of
the MiniBooNE LEE at the $<2\sigma$ confidence level. Next, we investigate a
phenomenological explanation of the MiniBooNE excess combining the $3+1$ model
with a dipole-coupled heavy neutral lepton (HNL). It is shown that a 500 MeV
HNL can accommodate the energy and angular distributions of the LEE at the
$2\sigma$ confidence level while avoiding stringent constraints derived from
MINER$\nu$A elastic scattering data. Finally, we discuss the Coherent
CAPTAIN-Mills experiment--a 10-ton light-based liquid argon detector at Los
Alamos National Laboratory. The background rejection achieved from a novel
Cherenkov-based reconstruction algorithm will enable world-leading sensitivity
to a number of beyond-the-Standard Model physics scenarios, including
dipole-coupled HNLs. | hep-ex |
Recent neutrino oscillation result with the IceCube experiment: The IceCube South Pole Neutrino Observatory is a Cherenkov detector
instrumented in a cubic kilometer of ice at the South Pole. IceCube's primary
scientific goal is the detection of TeV neutrino emissions from astrophysical
sources. At the lower center of the IceCube array, there is a subdetector
called DeepCore, which has a denser configuration that makes it possible to
lower the energy threshold of IceCube and observe GeV-scale neutrinos, opening
the window to atmospheric neutrino oscillations studies. Advances in physics
sensitivity have recently been achieved by employing Convolutional Neural
Networks to reconstruct neutrino interactions in the DeepCore detector. In this
contribution, the recent IceCube result from the atmospheric muon neutrino
disappearance analysis using the CNN-reconstructed neutrino sample is presented
and compared to the existing worldwide measurements. | hep-ex |
Athermal Phonon Sensors in Searches for Light Dark Matter: In recent years, theoretical and experimental interest in dark matter (DM)
candidates have shifted focus from primarily Weakly-Interacting Massive
Particles (WIMPs) to an entire suite of candidates with masses from the
zeV-scale to the PeV-scale to 30 solar masses. One particular recent
development has been searches for light dark matter (LDM), which is typically
defined as candidates with masses in the range of keV to GeV. In searches for
LDM, eV-scale and below detector thresholds are needed to detect the small
amount of kinetic energy that is imparted to nuclei in a recoil. One such
detector technology that can be applied to LDM searches is that of
Transition-Edge Sensors (TESs). Operated at cryogenic temperatures, these
sensors can achieve the required thresholds, depending on the optimization of
the design.
In this thesis, I will motivate the evidence for DM and the various DM
candidates beyond the WIMP. I will then detail the basics of TES
characterization, expand and apply the concepts to an athermal phonon
sensor--based Cryogenic PhotoDetector (CPD), and use this detector to carry out
a search for LDM at the surface. The resulting exclusion analysis provides the
most stringent limits in DM-nucleon scattering cross section (comparing to
contemporary searches) for a cryogenic detector for masses from 93 to 140 MeV,
showing the promise of athermal phonon sensors in future LDM searches.
Furthermore, unknown excess background signals are observed in this LDM search,
for which I rule out various possible sources and motivate stress-related
microfractures as an intriguing explanation. Finally, I will shortly discuss
the outlook of future searches for LDM for various detection channels beyond
nuclear recoils. | hep-ex |
Measurements of two-particle correlations in $e^+e^-$ collisions at 91
GeV with ALEPH archived data: Measurements of two-particle angular correlations of charged particles
emitted in hadronic $Z$ decays are presented. The archived $e^+e^-$
annihilation data at a center-of-mass energy of 91 GeV were collected with the
ALEPH detector at LEP between 1992 and 1995. The correlation functions are
measured over a broad range of pseudorapidity and full azimuth as a function of
charged particle multiplicity. No significant long-range correlation is
observed in either the lab coordinate analysis or the thrust coordinate
analysis, where the latter is sensitive to a medium expanding transverse to the
color string between the outgoing $q\bar{q}$ pair from $Z$ boson decays. The
associated yield distributions in both analyses are in better agreement with
the prediction from the PYTHIA v6.1 event generator than from HERWIG v7.1.5.
They provide new insights to showering and hadronization modeling. These
results serve as an important reference to the observed long-range correlation
in proton-proton, proton-nucleus, and nucleus-nucleus collisions. | hep-ex |
Search for "Invisible" Axion Dark Matter in the $3.3\text{-}4.2~μ$eV
Mass Range: We report the results from a haloscope search for axion dark matter in the
$3.3\text{-}4.2~{\mu}$eV mass range. This search excludes the axion-photon
coupling predicted by one of the benchmark models of "invisible" axion dark
matter, the KSVZ model. This sensitivity is achieved using a large-volume
cavity, a superconducting magnet, an ultra low noise Josephson parametric
amplifier, and sub-Kelvin temperatures. The validity of our detection procedure
is ensured by injecting and detecting blind synthetic axion signals. | hep-ex |
Rare $B$ decays at CMS: The Flavor Changing Neutral Current mediated decays $B \rightarrow
\mu^{+}\mu^{-}$ and $B^{0} \rightarrow K^{*0}\mu^{+}\mu^{-}$ provide high
sensitivity to new physics contributions. Sensitive observables include the
branching fraction, the muon forward-backward asymmetry, the fraction of
$K^{*0}$ longitudinal polarisation and the differential branching fraction. We
report herein the recent results from CMS on these decay modes. | hep-ex |
Measurement of $A_Γ$: The measurement of the charm CP violation observable $A_{\Gamma}$ using 1
fb$^{-1}$ of $pp$ collisions at $\sqrt{s}=7$ TeV recorded by the LHCb detector
in 2011 is presented. This new result is the most accurate to date. | hep-ex |
Kaon physics: Recent experimental progress: Numerous recent measurements of kaon decays are described, with an emphasis
on results offering constraints on chiral perturbation theory calculations. An
up-to-date estimate of |Vus|f+(0) based on semileptonic kaon decay rates is
presented. | hep-ex |
Measurement of direct photon pair production cross sections in ppbar
collisions at sqrt(s)=1.96 TeV: We present a measurement of direct photon pair production cross sections
using 4.2 fb-1 of data collected with the D0 detector at the Fermilab Tevatron
proton-antiproton Collider. We measure single differential cross sections as a
function of the diphoton mass, the transverse momentum of the diphoton system,
the azimuthal angle between the photons, and the polar scattering angle of the
photons, as well as the double differential cross sections considering the last
three kinematic variables in three diphoton mass bins. The results are compared
with different perturbative QCD predictions and event generators. | hep-ex |
Results on ultra-peripheral interactions in Pb-Pb and p-Pb collisions in
ALICE: Ultra-relativistic heavy ions generate strong electromagnetic fields which
offer the possibility to study $\gamma$-nucleus and $\gamma$-proton
interactions at the LHC in the so called ultra-peripheral collisions (UPC).
Here we report ALICE results on J/psi photoproduction measured in Pb-Pb
collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV and in p-Pb collisions at
$\sqrt{s_{\rm NN}}$ = 5.02 TeV. | hep-ex |
Cross-section measurements of top-quark pair production in association
with a hard photon at 13 TeV with the ATLAS detector: 25 years after the top quark's discovery, the Large Hadron Collider at CERN
produces proton-proton collision data on unprecedented scales at unprecedented
energies - and has heralded an era of top-quark precision measurements. The
production of a top-quark pair in association with a photon ($t\bar{t}\gamma$)
gives access to the electromagnetic top-photon coupling, one of the fundamental
properties of the top quark. Various extensions of the Standard Model predict
modifications of the coupling strength or structure, and deviations from the
Standard Model prediction of the $t\bar{t}\gamma$ production cross-section
would indicate new physics. With enough statistics available from the Large
Hadron Collider, the electron-muon channel has gained particular interest due
to its high signal purity and precise available theory predictions.
This thesis presents results with the full Run 2 dataset collected with the
ATLAS detector in proton-proton collisions at the Large Hadron Collider between
2015 and 2018 at 13 TeV centre-of-mass energy, corresponding to an integrated
luminosity of 139 fb$^{-1}$. In order to compare the results to fixed-order
calculations that include non-doubly-resonant diagrams, a combined measurement
of $t\bar{t}\gamma + tW\gamma$ is performed. The focus is placed on a
measurement of the fiducial inclusive cross-section in the electron-muon
channel. Furthermore, the ATLAS data is unfolded to parton level and
measurements of differential cross-sections as functions of several observables
are presented. Both fiducial inclusive and differential results are compared to
state-of-the-art fixed-order calculations at next-to-leading order in QCD. An
additional focus of the thesis is placed on studies to use machine-learning
techniques, in particular deep neural networks, for the identification of
prompt photons. | hep-ex |
First Observations of Separated Atmospheric Muon Neutrino and Muon
Anti-Neutrino Events in the MINOS Detector: The complete 5.4 kton MINOS far detector has been taking data since the
beginning of August 2003 at a depth of 2070 meters water-equivalent in the
Soudan mine, Minnesota. This paper presents the first MINOS observations of
muon neutrino and muon anti-neutrino charged-current atmospheric neutrino
interactions based on an exposure of 418 days. The ratio of upward to
downward-going events in the data is compared to the Monte Carlo expectation in
the absence of neutrino oscillations giving:
R_data(up/down)/R_MC(up/down) = 0.62^{+0.19}_{-0.14} (stat.) +- 0.02 (sys.).
An extended maximum likelihood analysis of the observed L/E distributions
excludes the null hypothesis of no neutrino oscillations at the 98 % confidence
level. Using the curvature of the observed muons in the 1.3 T MINOS magnetic
field muon neutrino and muon anti-neutrino interactions are separated. The
ratio of muon neutrino to muon anti-neutrino events in the data is compared to
the Monte Carlo expectation assuming neutrinos and anti-neutrinos oscillate in
same manner giving:
R_data(numubar/numu)/R_MC(numubar/numu) = 0.96^{+0.38}_{-0.27} (stat.) +-
0.15 (sys.), where the errors are the statistical and systematic uncertainties.
Although the statistics are limited, this is the first direct observation of
atmospheric neutrino interactions separately for muon neutrinos and muon
anti-neutrinos. | hep-ex |
Combined measurements of anomalous charged trilinear gauge-boson
couplings from diboson production in p-pbar collisions at sqrt(s)=1.96 TeV: We present measurements of the anomalous WWgamma and WWZ trilinear gauge
couplings from a combination of four diboson production and decay channels
using data collected by the D0 detector at the Fermilab Tevatron Collider.
These results represent the first high statistics combination of limits across
different diboson production processes at the Tevatron and use data
corresponding to an integrated luminosity of approximately 1 fb^-1. When
respecting SU(2)_L x U(1)_Y symmetry, we measure central values and 68% C.L.
allowed intervals of kappa_gamma=1.07^+0.16_-0.20, lambda =0.00^+0.05_-0.04 and
g_1^Z=1.05 +/- 0.06. We present the most stringent measurements to date for the
W boson magnetic dipole and electromagnetic quadrupole moments of
mu_W=2.02^+0.08_-0.09 (e/2M_W) and q_W=-1.00 +/- 0.09 (e/M^2_W), respectively. | hep-ex |
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