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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Inclusive and diferential cross section measurements of t(t)over-barb(b)over-bar production in the lepton plus jets channel at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurement of the Λ<sub>c</sub><SUP>+</SUP> to D<SUP>0</SUP> production ratio in peripheral PbPb collisions at √s<sub>NN</sub> = 5.02 TeV (vol 2024, 21, 2024)
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Study of CP violation in B<SUP>0</SUP> → DK*(892)<SUP>0</SUP> decays with D → Kπ(ππ), ππ(ππ), and KK final states
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAbe K, Bronner C, Hayato Y, et al., 2024,
Solar neutrino measurements using the full data period of Super-Kamiokande-IV
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Multiplicity dependence of σ<inf>ψ(2S)</inf>/σ<inf>J/ψ</inf> in pp collisions at √s = 13 TeV
, Journal of High Energy Physics, Vol: 2024The ratio of production cross-sections of ψ(2S) over J/ψ mesons as a function of charged-particle multiplicity in proton-proton collisions at a centre-of-mass energy s = 13 TeV is measured with a data sample collected by the LHCb detector, corresponding to an integrated luminosity of 658 pb−1. The ratio is measured for both prompt and non-prompt ψ(2S) and J/ψ mesons. When there is an overlap between the rapidity ranges over which multiplicity and charmonia production are measured, a multiplicity-dependent modification of the ratio is observed for prompt mesons. No significant multiplicity dependence is found when the ranges do not overlap. For non-prompt production, the ψ(2S)-to-J/ψ production ratio is roughly independent of multiplicity, irrespective of the rapidity range over which the multiplicity is measured. The results are compared to predictions of the co-mover model and agree well except in the low multiplicity region. The ratio of production cross-sections of ψ(2S) over J/ψ mesons are cross-checked with other measurements in di-lepton channels and found to be compatible.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Search for Bc+→π+μ+μ- decays and measurement of the branching fraction ratio B(Bc+→ψ(2S)π+)/B(Bc+→J/ψπ+)
, European Physical Journal C, Vol: 84, ISSN: 1434-6044The first search for nonresonant Bc+→π+μ+μ- decays is reported. The analysis uses proton–proton collision data collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9fb-1. No evidence for an excess of signal events over background is observed and an upper limit is set on the branching fraction ratio B(Bc+→π+μ+μ-)/B(Bc+→J/ψπ+)<2.1×10-4 at 90% confidence level. Additionally, an updated measurement of the ratio of the Bc+→ψ(2S)π+ and Bc+→J/ψπ+ branching fractions is reported. The ratio B(Bc+→ψ(2S)π+)/B(Bc+→J/ψπ+) is measured to be 0.254±0.018±0.003±0.005, where the first uncertainty is statistical, the second systematic, and the third is due to the uncertainties on the branching fractions of the leptonic J/ψ and ψ(2S) decays. This measurement is the most precise to date and is consistent with previous LHCb results.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of the branching fraction of B<sup>0</sup>→ J/ψπ<sup>0</sup> decays
, Journal of High Energy Physics, Vol: 2024The ratio of branching fractions between B0 → J/ψπ0 and B+ → J/ψK*+ decays is measured with proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The measured value is (Formula presented.) where the first uncertainty is statistical and the second is systematic. The branching fraction for B0 → J/ψπ0 decays is determined using the branching fraction of the normalisation channel, resulting in (Formula presented.) where the last uncertainty corresponds to that of the external input. This result is consistent with the current world average value and competitive with the most precise single measurement to date.
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Journal articleAyres Rocha D, Baptista de Souza Leite J, Bediaga IB, et al., 2024,
The LHCb Upgrade I
, Journal of Instrumentation, Vol: 19The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Measurement of simplified template cross sections of the Higgs boson produced in association with 𝑊 or 𝑍 bosons in the 𝐻 →𝑏¯𝑏 decay channel in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368Differential cross sections are measured for the standard model Higgs boson produced in association with vector bosons (𝑊, 𝑍) and decaying to a pair of 𝑏 quarks. Measurements are performed within the framework of the simplified template cross sections. The analysis relies on the leptonic decays of the 𝑊 and 𝑍 bosons, resulting in final states with 0, 1, or 2 electrons or muons. The Higgs boson candidates are either reconstructed from pairs of resolved 𝑏-tagged jets, or from single large-radius jets containing the particles arising from two 𝑏 quarks. Proton-proton collision data at √𝑠 =13 TeV, collected by the CMS experiment in 2016–2018 and corresponding to a total integrated luminosity of 138 fb−1, are analyzed. The inclusive signal strength, defined as the product of the observed production cross section and branching fraction relative to the standard model expectation, combining all analysis categories, is found to be 𝜇 =1.15+0.22−0.20. This corresponds to an observed (expected) significance of 6.3 (5.6) standard deviations.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at √sNN = 5.02 TeV with the LHCb detector
, Physical Review C, Vol: 109, ISSN: 2469-9985Flow harmonic coefficients, vn, which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02 TeV. The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features.
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Journal articleAbratenko P, Alterkait O, Andrade Aldana D, et al., 2024,
Measurement of nuclear effects in neutrino-argon interactions using generalized kinematic imbalance variables with the MicroBooNE detector
, Physical Review D, Vol: 109, ISSN: 2470-0010We present a set of new generalized kinematic imbalance variables that can be measured in neutrino scattering. These variables extend previous measurements of kinematic imbalance on the transverse plane and are more sensitive to modeling of nuclear effects. We demonstrate the enhanced power of these variables using simulation and then use the MicroBooNE detector to measure them for the first time. We report flux-integrated single- and double-differential measurements of charged-current muon neutrino scattering on argon using a topology with one muon and one proton in the final state as a function of these novel kinematic imbalance variables. These measurements allow us to demonstrate that the treatment of charged current quasielastic interactions in genie version 2 is inadequate to describe data. Further, they reveal tensions with more modern generator predictions particularly in regions of phase space where final state interactions are important.
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Journal articleCampbell JM, Diefenthaler M, Hobbs TJ, et al., 2024,
Event generators for high-energy physics experiments
, SCIPOST PHYSICS, Vol: 16, ISSN: 2542-4653 -
Journal articleAcampora G, Ahdida C, Albanese R, et al., 2024,
SND@LHC: the scattering and neutrino detector at the LHC
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleCMS Collaboration, Hayrapetyan A, Tumasyan A, et al., 2024,
Search for exotic decays of the Higgs boson to a pair of pseudoscalars in the μμbb and ττbb final states
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1434-6052A search for exotic decays of the Higgs boson (H) with a mass of 125GeV to a pair of light pseudoscalars a1 is performed in final states where one pseudoscalar decays to two b quarks and the other to a pair of muons or τ leptons. A data sample of proton-proton collisions at s=13TeV corresponding to an integrated luminosity of 138fb-1 recorded with the CMS detector is analyzed. No statistically significant excess is observed over the standard model backgrounds. Upper limits are set at 95% confidence level (CL) on the Higgs boson branching fraction to μμbb and to ττbb, via a pair of a1s. The limits depend on the pseudoscalar mass ma1 and are observed to be in the range (0.17-3.3) ×10-4 and (1.7-7.7) ×10-2 in the μμbb and ττbb final states, respectively. In the framework of models with two Higgs doublets and a complex scalar singlet (2HDM+S), the results of the two final states are combined to determine upper limits on the branching fraction B(H→a1a1→ℓℓbb) at 95% CL, with ℓ being a muon or a τ lepton. For different types of 2HDM+S, upper bounds on the branching fraction B(H→a1a1) are extracted from the combination of the two channels. In most of the Type II 2HDM+S parameter space, B(H→a1a1) values above 0.23 are excluded at 95% CL for ma1 values between 15 and 60GeV.
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Journal articlePec V, Kudryavtsev VA, Araujo HM, et al., 2024,
Muon-induced background in a next-generation dark matter experiment based on liquid xenon
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1124-1861Muon-induced neutrons can lead to potentially irreducible backgrounds in rare event search experiments. We have investigated the implication of laboratory depth on the muon-induced background in a future dark matter experiment capable of reaching the so-called neutrino floor. Our simulation study focused on a xenon-based detector with 70 tonnes of active mass, surrounded by additional veto systems plus a water shield. Two locations at the Boulby Underground Laboratory (UK) were analysed as examples: an experimental cavern in salt at a depth of 2850 m w. e. (similar to the location of the existing laboratory), and a deeper laboratory located in polyhalite rock at a depth of 3575 m w. e. Our results show that no cosmogenic background events are likely to survive standard analysis cuts for 10 years of operation at either location. The largest background component we identified comes from beta-delayed neutron emission from
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for an exotic decay of the Higgs boson into a Z boson and apseudoscalar particle in proton-proton collisions at √𝑠 = 13 TeV
, Physics Letters B: Nuclear Physics and Particle Physics, Vol: 852, ISSN: 0370-2693A search for an exotic decay of the Higgs boson to a Z boson and a light pseudoscalar particle (a), decaying to apair of leptons and a pair of photons, respectively, is presented. The search is based on proton-proton collisiondata at a center-of-mass energy of √𝑠 = 13TeV, collected with the CMS detector at the LHC and correspondingto an integrated luminosity of 138 fb−1. The analysis probes pseudoscalar masses 𝑚a between 1 and 30 GeV,leading to two pairs of well-isolated leptons and photons. Upper limits at 95% confidence level are set on theHiggs boson production cross section times its branching fraction to two leptons and two photons. The observed(expected) limits are in the range of 1.1–17.8 (1.7–17.9) fb within the probed 𝑚a interval. An excess of data abovethe expected standard model background with a local (global) significance of 2.6 (1.3) standard deviations isobserved for a mass hypothesis of 𝑚a = 3GeV. Limits on models involving axion-like particles, formulated as aneffective field theory, are also reported.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Development of the CMS detector for the CERN LHC Run 3
, Journal of Instrumentation, Vol: 19, ISSN: 1748-0221Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.
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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: 2470-0010 -
Journal articleMcGarrigle JM, Long KR, Prezado Y, 2024,
The FLASH effect-an evaluation of preclinical studies of ultra-high dose rate radiotherapy
, Frontiers in Oncology, Vol: 14, ISSN: 2234-943XFLASH radiotherapy (FLASH-RT) is a novel radiotherapy approach based on the use of ultra-high dose radiation to treat malignant cells. Although tumours can be reduced or eradicated using radiotherapy, toxicities induced by radiation can compromise healthy tissues. The FLASH effect is the observation that treatment delivered at an ultra-high dose rate is able to reduce adverse toxicities present at conventional dose rates. While this novel technique may provide a turning point for clinical practice, the exact mechanisms underlying the causes or influences of the FLASH effect are not fully understood. The study presented here uses data collected from 41 experimental investigations (published before March 2024) of the FLASH effect. Searchable databases were constructed to contain the outcomes of the various experiments in addition to values of beam parameters that may have a bearing on the FLASH effect. An in-depth review of the impact of the key beam parameters on the results of the experiments was carried out. Correlations between parameter values and experimental outcomes were studied. Pulse Dose Rate had positive correlations with almost all end points, suggesting viability of FLASH-RT as a new modality of radiotherapy. The collective results of this systematic review study suggest that beam parameter qualities from both FLASH and conventional radiotherapy can be valuable for tissue sparing and effective tumour treatment.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Prompt and nonprompt ψ(2<i>S</i>) production in <i>p</i>Pb collisions at √<i>s</i><sub>NN</sub>=8.16 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleDatta A, Mazumdar D, Banerjee S, et al., 2024,
Erratum to “Magnetic, magnetocaloric and critical behavior studies in Heusler compounds Co<inf>2-x</inf>Cr<inf>1+x</inf>Al” [J. Magn. Magn. Mater. 591 (2024) 171743] (Journal of Magnetism and Magnetic Materials (2024) 591, (S0304885324000337), (10.1016/j.jmmm.2024.171743))
, Journal of Magnetism and Magnetic Materials, Vol: 596, ISSN: 0304-8853In the original article (https://doi.org/10.1016/j.jmmm.2024.171743), the units of the parameters in Table 1, and the values of the parameters in Table 3 and Table 4 are difficult to understand for a reader. The actual form of Table 1, Table 3 and Table 4 are given below. [Table prsented]
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Journal articleChakrani J, Dolan S, Avanzini MB, et al., 2024,
Parametrized uncertainties in the spectral function model of neutrino charged-current quasielastic interactions for oscillation analyses
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleAbratenko P, Alterkait O, Andrade Aldana D, et al., 2024,
First Measurement of η Meson Production in Neutrino Interactions on Argon with MicroBooNE.
, Phys Rev Lett, Vol: 132We present a measurement of η production from neutrino interactions on argon with the MicroBooNE detector. The modeling of resonant neutrino interactions on argon is a critical aspect of the neutrino oscillation physics program being carried out by the DUNE and Short Baseline Neutrino programs. η production in neutrino interactions provides a powerful new probe of resonant interactions, complementary to pion channels, and is particularly suited to the study of higher-order resonances beyond the Δ(1232). We measure a flux-integrated cross section for neutrino-induced η production on argon of 3.22±0.84(stat)±0.86(syst) 10^{-41} cm^{2}/nucleon. By demonstrating the successful reconstruction of the two photons resulting from η production, this analysis enables a novel calibration technique for electromagnetic showers in GeV accelerator neutrino experiments.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Search for <i>CP</i> violation in the phase space of D<SUP>0</SUP> <i>→</i> π<SUP> <i>-</i> </SUP>π<SUP>+</SUP>π<SUP>0</SUP> decays with the energy test (Sep, 129, 2023)
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Observation of the B<inf>c</inf><sup>+</sup>→J/ψπ<sup>+</sup>π<sup>0</sup> decay
, Journal of High Energy Physics, Vol: 2024The first observation of the Bc+→J/ψπ+π0 decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV. The ratio of its branching fraction relative to the Bc+→J/ψπ+ channel is measured to be (Formula presented.) where the first uncertainty is statistical, the second systematic and the third related to imprecise knowledge of the branching fractions for B+ → J/ψK*+ and Bc+→J/ψπ+ decays, which are used to determine the π0 detection efficiency. The π+π0 mass spectrum is found to be consistent with the dominance of an intermediate ρ+ contribution in accordance with a model based on QCD factorisation.
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Journal articleKotani T, Miyata Y, Tsuboyama Y, et al., 2024,
Local intracellular stiffening of ascidian embryo in cleavage developmental stage observed by atomic force microscopy
, JAPANESE JOURNAL OF APPLIED PHYSICS, Vol: 63, ISSN: 0021-4922 -
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 supersymmetry in final states with disappearing tracks in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368A 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 137 fb−1. The search is performed over final states characterized by varying numbers of jets, 𝑏-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 d𝐸/d𝑥 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 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 √s=13 TeV
, Physical Review D (particles, fields, gravitation, and cosmology), Vol: 109, ISSN: 2470-0010A search for the production of a top quark in association with a photon and additional jets via flavorchanging neutral current interactions is presented. The analysis uses proton-proton collision data recordedby the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of138 fb−1. The search is performed by looking for processes where a single top quark is produced inassociation with a photon, or a pair of top quarks where one of the top quarks decays into a photon and anup or charm quark. Events with an electron or a muon, a photon, one or more jets, and missing transversemomentum are selected. Multivariate analysis techniques are used to discriminate signal and standardmodel 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: Bðt → uγÞ <0.95 × 10−5 (1.20 × 10−5) and Bðt → cγÞ < 1.51 × 10−5 (1.54 × 10−5) at 95% confidence level, assuminga single nonzero coupling at a time. The obtained limit for Bðt → uγÞ is similar to the current best limit,while the limit for Bðt → cγÞ is significantly tighter than previous results.
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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: 19, ISSN: 1748-0221
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