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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurement of Ξ<sub>c</sub><SUP>+</SUP> production in <i>p</i>Pb collisions at √<i>s<sub>NN</sub></i>=8.16 TeV at LHCb
, PHYSICAL REVIEW C, Vol: 109, ISSN: 2469-9985 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for flavor changing neutral current interactions of the top quark in final states with a photon and additional jets in proton-proton collisions at Formula Presented
, Physical Review D, Vol: 109, ISSN: 2470-0010A search for the production of a top quark in association with a photon and additional jets via flavor changing neutral current interactions is presented. The analysis uses proton-proton collision data recorded by the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of Formula Presented. The search is performed by looking for processes where a single top quark is produced in association with a photon, or a pair of top quarks where one of the top quarks decays into a photon and an up or charm quark. Events with an electron or a muon, a photon, one or more jets, and missing transverse momentum are selected. Multivariate analysis techniques are used to discriminate signal and standard model background processes. No significant deviation is observed over the predicted background. Observed (expected) upper limits are set on the branching fractions of top quark decays: Formula Presented (Formula Presented) and Formula Presented (Formula Presented) at 95% confidence level, assuming a single nonzero coupling at a time. The obtained limit for Formula Presented is similar to the current best limit, while the limit for Formula Presented is significantly tighter than previous results.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for supersymmetry in final states with disappearing tracks in proton-proton collisions at Formula Presented
, Physical Review D, Vol: 109, ISSN: 2470-0010A search is presented for charged, long-lived supersymmetric particles in final states with one or more disappearing tracks. The search is based on data from proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the CERN LHC between 2016 and 2018, corresponding to an integrated luminosity of Formula Presented. The search is performed over final states characterized by varying numbers of jets, Formula Presented-tagged jets, electrons, and muons. The length of signal-candidate tracks in the plane perpendicular to the beam axis is used to characterize the lifetimes of wino- and Higgsino-like charginos produced in the context of the minimal supersymmetric standard model. The Formula Presented energy loss of signal-candidate tracks is used to increase the sensitivity to charginos with a large mass and thus a small Lorentz boost. The observed results are found to be statistically consistent with the background-only hypothesis. Limits on the pair-production cross section of gluinos and squarks are presented in the framework of simplified models of supersymmetric particle production and decay, and for electroweakino production based on models of wino and Higgsino dark matter. The limits presented are the most stringent to date for scenarios with light third-generation squarks and a wino- or Higgsino-like dark matter candidate capable of explaining the observed dark matter relic density.
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Journal articleWester T, Abe K, Bronner C, et al., 2024,
Atmospheric neutrino oscillation analysis with neutron tagging and an expanded fiducial volume in Super-Kamiokande I-V
, Physical Review D, Vol: 109, ISSN: 2470-0010We present a measurement of neutrino oscillation parameters with the Super-Kamiokande detector using atmospheric neutrinos from the complete pure-water SK I-V (April 1996-July 2020) dataset, including events from an expanded fiducial volume. The dataset corresponds to 6511.3 live days and an exposure of 484.2 kiloton-years. Measurements of the neutrino oscillation parameters Δm322, sin2θ23, sin2θ13, δCP, and the preference for the neutrino mass ordering are presented with atmospheric neutrino data alone, and with constraints on sin2θ13 from reactor neutrino experiments. Our analysis including constraints on sin2θ13 favors the normal mass ordering at the 92.3% level.
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Journal articleAcar B, Adamov G, Adloff C, et al., 2024,
Timing performance of the CMS High Granularity Calorimeter prototype
, Journal of Instrumentation, Vol: 19This paper describes the experience with the calibration, reconstruction and evaluation of the timing capabilities of the CMS HGCAL prototype in the beam tests in 2018. The calibration procedure includes multiple steps and corrections ranging from tens of nanoseconds to a few hundred picoseconds. The timing performance is studied using signals from positron beam particles with energies between 20 GeV and 300 GeV. The performance is studied as a function of particle energy against an external timing reference as well as standalone by comparing the two different halves of the prototype. The timing resolution is found to be 60 ps for single-channel measurements and better than 20 ps for full showers at the highest energies, setting excellent perspectives for the HGCAL calorimeter performance at the HL-LHC.
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Journal articleHoenig D, Thielemann F, Karpa L, et al., 2024,
Trapping Ion Coulomb Crystals in an Optical Lattice.
, Phys Rev Lett, Vol: 132We report the optical trapping of multiple ions localized at individual lattice sites of a one-dimensional optical lattice. We observe a fivefold increased range of axial dc-electric field strength for which ions can be optically trapped with high probability and an increase of the axial eigenfrequency by 2 orders of magnitude compared to an optical dipole trap without interference but of similar intensity. Our findings motivate an alternative pathway to extend arrays of trapped ions in size and dimension, enabling quantum simulations with particles interacting at long range.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Amplitude Analysis of the <i>B</i><SUP>0</SUP> - <i>K</i>*<SUP>0</SUP> μ<SUP>+</SUP>μ<SUP>-</SUP> Decay
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Conference paperFujii Y, 2024,
Charged Lepton Flavour Violation: experimental activities
Charged lepton flavour violation processes are powerful probes to investigate new physics beyond the standard model of particle physics. There are several ongoing activities and future projects. All of them are going to achieve the levels of sensitivity which are able to explore many new physics scenarios, corresponding to higher energy scale than that is directly accessible with present particle colliders. This paper introduces the recent and present experimental efforts in this area of searches, especially focusing on MEG, MEG2, Mu3e, Mu2e and COMET.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for long-lived heavy neutral leptons with lepton flavour conserving or violating decays to a jet and a charged lepton
, Journal of High Energy Physics, Vol: 2024<jats:title>A<jats:sc>bstract</jats:sc> </jats:title><jats:p>A search for long-lived heavy neutral leptons (HNLs) is presented, which considers the hadronic final state and coupling scenarios involving all three lepton generations in the 2–20 GeV HNL mass range for the first time. Events comprising two leptons (electrons or muons) and jets are analyzed in a data sample of proton-proton collisions, recorded with the CMS experiment at the CERN LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. A novel jet tagger, based on a deep neural network, has been developed to identify jets from an HNL decay using various features of the jet and its constituent particles. The network output can be used as a powerful discriminating tool to probe a broad range of HNL lifetimes and masses. Contributions from background processes are determined from data. No excess of events in data over the expected background is observed. Upper limits on the HNL production cross section are derived as functions of the HNL mass and the three coupling strengths <jats:italic>V</jats:italic><jats:sub><jats:italic>ℓ</jats:italic>N</jats:sub> to each lepton generation <jats:italic>ℓ</jats:italic> and presented as exclusion limits in the coupling-mass plane, as lower limits on the HNL lifetime, and on the HNL mass. In this search, the most stringent limit on the coupling strength is obtained for pure muon coupling scenarios; values of <jats:italic>|</jats:italic><jats:inline-formula><jats:alternatives><jats:tex-math>$$ {V}_{\mu \textrm{N}}^2 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>V</mml:mi> <mml:m
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Observation of WWγ Production and Search for Hγ Production in Proton-Proton Collisions at √ s=13 TeV
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
New Structures in the J=ψJ=ψ Mass Spectrum in Proton-Proton Collisions at √ s=13 TeV
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurement of <i>J</i>/ψ-pair production in <i>pp</i> collisions at √<i>s</i>=13 TeV and study of gluon transverse-momentum dependent PDFs
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Observation of Ξ<sub>b</sub><SUP>0</SUP>→ Ξ<sub>c</sub> <SUP>+</SUP> D<sub>s</sub><SUP>-</SUP> and Ξ<sub>b</sub><SUP>0</SUP> c D- s decays
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Determination of short- and long-distance contributions in B0 →k∗0μ+μ- decays
, Physical Review D, Vol: 109, ISSN: 2470-0010An amplitude analysis of the B0→K∗0μ+μ- decay is presented. The analysis is based on data collected by the LHCb experiment from proton-proton collisions at s=7, 8 and 13 TeV, corresponding to an integrated luminosity of 4.7 fb-1. For the first time, Wilson coefficients and nonlocal hadronic contributions are accessed directly from the unbinned data, where the latter are parametrized as a function of q2 with a polynomial expansion. Wilson coefficients and nonlocal hadronic parameters are determined under two alternative hypotheses: the first relies on experimental information alone, while the second one includes information from theoretical predictions for the nonlocal contributions. Both models obtain similar results for the parameters of interest. The overall level of compatibility with the Standard Model is evaluated to be between 1.8 and 1.9 standard deviations when looking at the C9 Wilson coefficient alone, and between 1.3 and 1.4 standard deviations when considering the full set of C9,C10,C9′ and C10′ Wilson coefficients. The ranges reflect the theoretical assumptions made in the analysis.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for dark matter particles in W<sup>+</sup>W<sup>−</sup> events with transverse momentum imbalance in proton-proton collisions at s = 13 TeV
, Journal of High Energy Physics, Vol: 2024A search for dark matter particles is performed using events with a pair of W bosons and large missing transverse momentum. Candidate events are selected by requiring one or two leptons (ℓ = electrons or muons). The analysis is based on proton-proton collision data collected at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC and corresponding to an integrated luminosity of 138 fb−1. No significant excess over the expected standard model background is observed in the ℓνqq and 2ℓ2ν final states of the W+W− boson pair. Limits are set on dark matter production in the context of a simplified dark Higgs model, with a dark Higgs boson mass above the W+W− mass threshold. The dark matter phase space is probed in the mass range 100–300 GeV, extending the scope of previous searches. Current exclusion limits are improved in the range of dark Higgs masses from 160 to 250 GeV, for a dark matter mass of 200 GeV.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Curvature-bias corrections using a pseudomass method
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleStray B, Ennis O, Hedges S, et al., 2024,
Centralized design and production of the ultra-high vacuum and laser-stabilization systems for the AION ultra-cold strontium laboratories
, AVS Quantum Science, Vol: 6, ISSN: 2639-0213This paper outlines the centralized design and production of the ultra-high-vacuum sidearm and laser-stabilization systems for the AION Ultra-Cold Strontium Laboratories. Commissioning data on the residual gas and steady-state pressures in the sidearm chambers, on magnetic field quality, on laser stabilization, and on the loading rate for the 3D magneto-optical trap are presented. Streamlining the design and production of the sidearm and laser stabilization systems enabled the AION Collaboration to build and equip in parallel five state-of-the-art Ultra-Cold Strontium Laboratories within 24 months by leveraging key expertise in the collaboration. This approach could serve as a model for the development and construction of other cold atom experiments, such as atomic clock experiments and neutral atom quantum computing systems, by establishing dedicated design and production units at national laboratories.
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Journal articleQue Z, Fan H, Loo M, et al., 2024,
LL-GNN: Low Latency Graph Neural Networks on FPGAs for High Energy Physics
, ACM TRANSACTIONS ON EMBEDDED COMPUTING SYSTEMS, Vol: 23, ISSN: 1539-9087 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Measurements of azimuthal anisotropy of nonprompt D<SUP>0</SUP> mesons in PbPb collisions at √s<sub>NN</sub>=5.02 TeV
, PHYSICS LETTERS B, Vol: 850, ISSN: 0370-2693 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Study of azimuthal anisotropy of γ(1S) mesons in pPb collisions at √S<sub>NN</sub>=8.16 TeV
, PHYSICS LETTERS B, Vol: 850, ISSN: 0370-2693 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for new Higgs bosons via same-sign top quark pair production in association with a jet in proton-proton collisions at √s=13 TeV
, PHYSICS LETTERS B, Vol: 850, ISSN: 0370-2693 -
Journal articlePasatembou E, Baynham CFA, Buchmuller O, et al., 2024,
Progress toward ultra-cold Sr for the AION project-A red MOT and an optical-heterodyne diagnostic tool for injection-locked laser diodes
, AVS QUANTUM SCIENCE, Vol: 6 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurement of the CKM angle γ in the B<SUP>0</SUP>→DK <SUP>*0</SUP> channel using self-conjugate D→ K<sub>S</sub><SUP>0</SUP>h<SUP>+</SUP> h<SUP>-</SUP> decays
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Enhanced Production of Λ_{b}^{0} Baryons in High-Multiplicity pp Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 132The production rate of Λ_{b}^{0} baryons relative to B^{0} mesons in pp collisions at a center-of-mass energy sqrt[s]=13 TeV is measured by the LHCb experiment. The ratio of Λ_{b}^{0} to B^{0} production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e^{+}e^{-} collisions, and increases by a factor of ∼2 with increasing multiplicity. At relatively low transverse momentum, the ratio of Λ_{b}^{0} to B^{0} cross sections is higher than what is measured in e^{+}e^{-} collisions, but converges with the e^{+}e^{-} ratio as the momentum increases. These results imply that the evolution of heavy b quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Observation of Cabibbo-Suppressed Two-Body Hadronic Decays and Precision Mass Measurement of the Ω<SUP>0</SUP><sub>c </sub>Baryon
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Two-particle Bose-Einstein correlations and their Lévy parameters in PbPb collisions at<i> √sNN</i>=5.02 TeV
, PHYSICAL REVIEW C, Vol: 109, ISSN: 2469-9985 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Study of <i>B<sub>c</sub></i><SUP>+</SUP> → χ<i><sub>c</sub></i> π<SUP>+</SUP> decays
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleArmano M, Audley H, Baird J, et al., 2024,
Sensor noise in<i> LISA</i><i> Pathfinder:</i> Laser frequency noise and its coupling to the optical test mass readout
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
A model-independent measurement of the CKM angle γ in partially reconstructed B<SUP>±</SUP>→D<SUP>∗</SUP>h<SUP>± </SUP>decays with D→K<SUP>0</SUP><sub>S</sub>h<SUP>+</SUP>h<SUP>-</SUP>(h=π,K)
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articlePal K, Das I, 2024,
Exploring the exchange bias of Gd and MnPt: A combined structural and magnetic investigation
, Thin Solid Films, Vol: 790, ISSN: 0040-6090Magnetic manipulation in thin films is essential for modern technology. Extensive studies on exchange bias with antiferromagnetic materials and transition metals exist, but research on rare earth elements is limited. This study investigates the formation of the L10-MnPt phase and a ferromagnetic-like Gd phase on Si/SiO2 thin films. We observed thickness-dependent anisotropic magnetic fields in Gd thin films and thickness-dependent exchange bias in the heterojunctions. These findings enhance our understanding of the magnetic properties of MnPt, Gd and the multilayer heterostructure.
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