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Journal articleArmano M, Audley H, Baird J, et al., 2024,
Tilt-to-length coupling in LISA Pathfinder: Long-term stability
, PHYSICAL REVIEW D, Vol: 110, ISSN: 2470-0010 -
Journal articleCms Collaboration T, 2024,
Observation ofγγ→ττin proton-proton collisions and limits on the anomalous electromagnetic moments of the τ lepton.
, Rep Prog Phys, Vol: 87The production of a pair of τ leptons via photon-photon fusion,γγ→ττ, is observed for the first time in proton-proton collisions, with a significance of 5.3 standard deviations. This observation is based on a data set recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb-1. Events with a pair of τ leptons produced via photon-photon fusion are selected by requiring them to be back-to-back in the azimuthal direction and to have a minimum number of charged hadrons associated with their production vertex. The τ leptons are reconstructed in their leptonic and hadronic decay modes. The measured fiducial cross section ofγγ→ττisσobsfid=12.4-3.1+3.8fb. Constraints are set on the contributions to the anomalous magnetic moment (aτ) and electric dipole moments (dτ) of the τ lepton originating from potential effects of new physics on theγττvertex:aτ=0.0009-0.0031+0.0032and|dτ|<2.9×10-17ecm(95% confidence level), consistent with the standard model.
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Journal articleAbed Abud A, Abi B, Acciarri R, et al., 2024,
Performance of a Modular Ton-Scale Pixel-Readout Liquid Argon Time Projection Chamber
, Instruments, Vol: 8The Module-0 Demonstrator is a single-phase 600 kg liquid argon time projection chamber operated as a prototype for the DUNE liquid argon near detector. Based on the ArgonCube design concept, Module-0 features a novel 80k-channel pixelated charge readout and advanced high-coverage photon detection system. In this paper, we present an analysis of an eight-day data set consisting of 25 million cosmic ray events collected in the spring of 2021. We use this sample to demonstrate the imaging performance of the charge and light readout systems as well as the signal correlations between the two. We also report argon purity and detector uniformity measurements and provide comparisons to detector simulations.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Transverse polarization measurement of Λ hyperons in pNe collisions at sNN = 68.4 GeV with the LHCb detector
, Journal of High Energy Physics, Vol: 2024A measurement of the transverse polarization of the Λ and Λ¯ hyperons in pNe fixed-target collisions at s<inf>NN</inf> = 68.4 GeV is presented using data collected by the LHCb detector. The polarization is studied using the decay Λ → pπ<sup>−</sup> together with its charge conjugated process, the integrated values measured are (Formula presented.) Furthermore, the results are shown as a function of the Feynman x variable, transverse momentum, pseudorapidity and rapidity of the hyperons, and are compared with previous measurements.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Search for the rare decay of charmed baryon Λc+ into the pμ+μ- final state
, Physical Review D, Vol: 110, ISSN: 2470-0010A search for the nonresonant Λc+→pμ+μ- decay is performed using proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the LHCb experiment, corresponding to an integrated luminosity of 5.4 fb-1. No evidence for the decay is found in the dimuon invariant-mass regions where the expected contributions of resonances is subdominant. The upper limit on the branching fraction of the Λc+→pμ+μ- decay is determined to be 2.9(3.2)×10-8 at 90%(95%) confidence level. The branching fractions in the dimuon invariant-mass regions dominated by the η, ρ and ω resonances are also determined.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for bottom-type vectorlike quark pair production in dileptonic and fully hadronic final states in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D, Vol: 110, ISSN: 2470-0010A search is described for the production of a pair of bottom-type vectorlike quarks (𝐵 VLQs) with mass greater than 1000 GeV. Each 𝐵 VLQ decays into a 𝑏 quark and a Higgs boson, a 𝑏 quark and a 𝑍 boson, or a 𝑡 quark and a 𝑊 boson. This analysis considers both fully hadronic final states and those containing a charged lepton pair from a 𝑍 boson decay. The products of the 𝐻 →𝑏𝑏 boson decay and of the hadronic 𝑍 or 𝑊 boson decays can be resolved as two distinct jets or merged into a single jet, so the final states are classified by the number of reconstructed jets. The analysis uses data corresponding to an integrated luminosity of 138 fb−1 collected in proton-proton collisions at √𝑠 =13 TeV with the CMS detector at the LHC from 2016 to 2018. No excess over the expected background is observed. Lower limits are set on the 𝐵 VLQ mass at the 95% confidence level. These depend on the 𝐵 VLQ branching fractions and are 1570 and 1540 GeV for 100% 𝐵 →𝑏𝐻 and 100% 𝐵 →𝑏𝑍, respectively. In most cases, the mass limits obtained exceed previous limits by at least 100 GeV.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for a resonance decaying to a W boson and a photon in proton-proton collisions at s = 13 TeV using leptonic W boson decays
, Journal of High Energy Physics, Vol: 2024A search for a new charged particle X with mass between 0.3 and 2.0 TeV decaying to a W boson and a photon is presented, using proton-proton collision data at a center-of-mass energy of 13 TeV, collected by the CMS experiment and corresponding to an integrated luminosity of 138 fb<sup>−1</sup>. Particle X has electric charge ±1 and is assumed to have spin 0. The search is performed using the electron and muon decays of the W boson. No significant excess above the predicted background is observed. The upper limit at 95% confidence level on the product of the production cross section of the X and its branching fraction to a W boson and a photon is found to be 94 (137) fb for a 0.3 TeV resonance and 0.75 (0.81) fb for a 2.0 TeV resonance, for an X width-to-mass ratio of 0.01% (5%). This search presents the most stringent constraints to date on the existence of such resonances across the probed mass range. A statistical combination with an earlier study based on the hadronic decay mode of the W boson is also performed, and the upper limit at 95% confidence level for a 2.0 TeV resonance is reduced to 0.50 (0.63) fb for an X width-to-mass ratio of 0.01% (5%).
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Comprehensive analysis of local and nonlocal amplitudes in the B0→ K*0μ+μ− decay
, Journal of High Energy Physics, Vol: 2024A comprehensive study of the local and nonlocal amplitudes contributing to the decay B<sup>0</sup> → K<sup>*0</sup>(→ K<sup>+</sup>π<sup>−</sup>)μ<sup>+</sup>μ<sup>−</sup> is performed by analysing the phase-space distribution of the decay products. The analysis is based on pp collision data corresponding to an integrated luminosity of 8.4 fb<sup>−1</sup> collected by the LHCb experiment. This measurement employs for the first time a model of both one-particle and two-particle nonlocal amplitudes, and utilises the complete dimuon mass spectrum without any veto regions around the narrow charmonium resonances. In this way it is possible to explicitly isolate the local and nonlocal contributions and capture the interference between them. The results show that interference with nonlocal contributions, although larger than predicted, only has a minor impact on the Wilson Coefficients determined from the fit to the data. For the local contributions, the Wilson Coefficient C<inf>9</inf>, responsible for vector dimuon currents, exhibits a 2.1σ deviation from the Standard Model expectation. The Wilson Coefficients C<inf>10</inf>, C<inf>9</inf><sup>′</sup> and C<inf>10</inf><sup>′</sup> are all in better agreement than C<inf>9</inf> with the Standard Model and the global significance is at the level of 1.5σ. The model used also accounts for nonlocal contributions from B<sup>0</sup>→ K<sup>*0</sup>[τ<sup>+</sup>τ<sup>−</sup>→ μ<sup>+</sup>μ<sup>−</sup>] rescattering, resulting in the first direct measurement of the bsττ vector effective-coupling C<inf>9τ</inf>.
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Journal articleOdagiu P, Que Z, Duarte J, et al., 2024,
Ultrafast jet classification at the HL-LHC
, Machine Learning: Science and Technology, Vol: 5, ISSN: 2632-2153Three machine learning models are used to perform jet origin classification. These models are optimized for deployment on a field-programmable gate array device. In this context, we demonstrate how latency and resource consumption scale with the input size and choice of algorithm. Moreover, the models proposed here are designed to work on the type of data and under the foreseen conditions at the CERN large hadron collider during its high-luminosity phase. Through quantization-aware training and efficient synthetization for a specific field programmable gate array, we show that O(100) ns inference of complex architectures such as Deep Sets and Interaction Networks is feasible at a relatively low computational resource cost.
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Journal articleMcGarrigle JM, Long KR, Prezado Y, 2024,
On the significance of the different geometrical and dosimetric parameters in microbeam and minibeam radiation therapy a retrospective evaluation
, Frontiers in Oncology, Vol: 14, ISSN: 2234-943XIntroduction: Spatially Fractionated Radiation Therapy (SFRT) is an unconventional therapeutic approach with the potential to disrupt the classical paradigms of conventional radiation therapy. The high spatial dose modulation in SFRT is believed to activate distinct radiobiological mechanisms which lead to remarkable increases in normal tissue tolerance. To make optimal use of SFRT and its benefits, a deeper understanding of the biological response and its relationship with the complex dosimetric and geometric components of SFRT is essential.Method: A retrospective evaluation of preclinical studies was conducted to gain insight into the dosimetric and geometric parameters that are most correlated with normal tissue response. Current literature evaluates the response of tissue to MBRT and MRT according to various end points, e.g. the level of desquamation, degree of necrosis, or the amount of malcalcification. A set of metrics was developed to allow a quantitative comparison of these results.Results: The strongest correlations were observed with the doses in both the peaks and valleys as well as the ratio of the area covered by the peak over the total area. This emphasises the geometry of the beam. MBRT challenged previous uniform dose-distribution paradigms by highlighting the critical role of Peak Dose alongside Valley Dose in tissue sparing whereas MRT underscores the significant influence of geometric beam parameters on tissue preservation.Discussion: The data exhibits variability in the results obtained using different animal models and endpoints and additional research is warranted to explore the trends observed in this study under controlled conditions.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Performance of CMS muon reconstruction from proton-proton to heavy ion collisions
, Journal of Instrumentation, Vol: 19, ISSN: 1748-0221The performance of muon tracking, identification, triggering, momentum resolution, and momentum scale has been studied with the CMS detector at the LHC using data collected at √(sNN) = 5.02 TeV in proton-proton (pp) and lead-lead (PbPb) collisions in 2017 and 2018, respectively, and at √(sNN) = 8.16 TeV in proton-lead (pPb) collisions in 2016. Muon efficiencies, momentum resolutions, and momentum scales are compared by focusing on how the muon reconstruction performance varies from relatively small occupancy pp collisions to the larger occupancies of pPb collisions and, finally, to the highest track multiplicity PbPb collisions. We find the efficiencies of muon tracking, identification, and triggering to be above 90% throughout most of the track multiplicity range. The momentum resolution and scale are unaffected by the detector occupancy. The excellent muon reconstruction of the CMS detector enables precision studies across all available collision systems.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Performance of the CMS electromagnetic calorimeter in pp collisions at √s = 13 TeV
, Journal of Instrumentation, Vol: 19, Pages: P09004-P09004, ISSN: 1748-0221The operation and performance of the Compact Muon Solenoid (CMS) electromagnetic calorimeter (ECAL) are presented, based on data collected in pp collisions at √s =13 TeV at the CERN LHC, in the years from 2015 to 2018 (LHC Run 2), corresponding to an integrated luminosity of 151 fb-1. The CMS ECAL is a scintillating lead-tungstate crystal calorimeter, with a silicon strip preshower detector in the forward region that provides precise measurements of the energy and the time-of-arrival of electrons and photons. The successful operation of the ECAL is crucial for a broad range of physics goals, ranging from observing the Higgs boson and measuring its properties, to other standard model measurements and searches for new phenomena. Precise calibration, alignment, and monitoring of the ECAL response are important ingredients to achieve these goals. To face the challenges posed by the higher luminosity, which characterized the operation of the LHC in Run 2, the procedures established during the 2011–2012 run of the LHC have been revisited and new methods have been developed for the energy measurement and for the ECAL calibration. The energy resolution of the calorimeter, for electrons from Z boson decays reaching the ECAL without significant loss of energy by bremsstrahlung, was better than 1.8%, 3.0%, and 4.5% in the |η| intervals [0.0,0.8], [0.8,1.5], [1.5, 2.5], respectively. This resulting performance is similar to that achieved during Run 1 in 2011–2012, in spite of the more severe running conditions.
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Journal articleAalbers J, Akerib DS, Al Musalhi AK, et al., 2024,
Probing the scalar WIMP-pion coupling with the first LUX-ZEPLIN data
, Communications Physics, Vol: 7, ISSN: 2399-3650Weakly interacting massive particles (WIMPs) may interact with a virtual pion that is exchanged between nucleons. This interaction channel is important to consider in models where the spin-independent isoscalar channel is suppressed. Using data from the first science run of the LUX-ZEPLIN dark matter experiment, containing 60 live days of data in a 5.5 tonne fiducial mass of liquid xenon, we report the results on a search for WIMP-pion interactions. We observe no significant excess and set an upper limit of 1.5 × 10−46 cm2 at a 90% confidence level for a WIMP mass of 33 GeV/c2 for this interaction.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Observation of strangeness enhancement with charmed mesons in high-multiplicity <i>p</i>Pb collisions at √<i>s</i><sub>NN</sub>=8.16 TeV
, PHYSICAL REVIEW D, Vol: 110, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
First observation of Λ<i><sub>b</sub></i><SUP>0</SUP> → Σ<i><sub>c</sub></i><SUP>(</SUP>*<SUP>)+ +</SUP> <i>D</i><SUP>(</SUP>*<SUP>) -</SUP> <i>K</i><SUP>-</SUP> decays
, PHYSICAL REVIEW D, Vol: 110, ISSN: 2470-0010 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of multijet azimuthal correlations and determination of the strong coupling in proton-proton collisions at s = 13 TeV
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1124-1861A measurement is presented of a ratio observable that provides a measure of the azimuthal correlationsamong jets with large transverse momentum pT . This observable is measured in multijet events over the range of pT = 360–3170 GeV based on data collected by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 134 fb−1 . The results are compared with predictions fromMonte Carlo parton-shower event generator simulations, aswell as with fixed-order perturbative quantum chromodynamics (pQCD) predictions at next-to-leading-order (NLO) accuracy obtained with different parton distribution functions (PDFs) and corrected for nonperturbative and electroweak effects. Data and theory agree within uncertainties. From the comparison of the measured observable with the pQCD prediction obtained with the NNPDF3.1 NLO PDFs, the strong coupling at the Z boson mass scale is αS(mZ) = 0.1177 ± 0.0013 (exp)+0.0116−0.0073 (theo) = 0.1177+0.0117−0.0074 , where the total uncertainty is dominated by the scale dependenceof the fixed-order predictions. A test of the running of αS inthe TeV region shows no deviation from the expected NLOpQCD behaviour.
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Journal articleArmano M, Audley H, Baird J, et al., 2024,
In-depth analysis of LISA Pathfinder performance results: Time evolution, noise projection, physical models, and implications for LISA
, Physical Review D, Vol: 110, ISSN: 2470-0010We present an in-depth analysis of the LISA Pathfinder differential acceleration performance over the entire course of its science operations, spanning approximately 500 days. We find: (1) The evolution of the Brownian noise that dominates the acceleration amplitude spectral density (ASD), for frequencies f≳1 mHz, is consistent with the decaying pressure due to the outgassing of a single gaseous species. (2) Between f=36 μHz and 1 mHz, the acceleration ASD shows a 1/f tail in excess of the Brownian noise of almost constant amplitude, with ≃20% fluctuations over a period of a few days, with no particular time pattern over the course of the mission. (3) At the lowest considered frequency of f=18 μHz, the ASD significantly deviates from the 1/f behavior, because of temperature fluctuations that appear to modulate a quasistatic pressure gradient, sustained by the asymmetries of the outgassing pattern. We also present the results of a projection of the observed acceleration noise on the potential sources for which we had either a direct correlation measurement or a quantitative estimate from dedicated experiments. These sources account for approximately 40% of the noise power in the 1/f tail. Finally, we analyze the possible sources of the remaining unexplained fraction and identify the possible measures that may be taken to keep those under control in LISA.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Amplitude analysis of the radiative decay B<sub>s</sub><SUP>0</SUP> → K<SUP>+</SUP>K<SUP>-</SUP>γ
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Combination of measurements of the top quark mass from data collected by the ATLAS and CMS experiments at sqrt[s]=7 and 8 TeV
, Physical Review Letters, Vol: 132, ISSN: 0031-9007A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The datasets used correspond to an integrated luminosity of up to 5 and 20 fb−1 of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak 𝑡 channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is 𝑚𝑡=172.52±0.14(stat)±0.30(syst) GeV, with a total uncertainty of 0.33 GeV.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of Energy Correlators inside Jets and Determination of the Strong Coupling α_{S}(m_{Z})
, Physical Review Letters, Vol: 133, ISSN: 0031-9007Energy correlators that describe energy-weighted distances between two or three particles in a hadronic jet are measured using an event sample of √𝑠=13 TeV proton-proton collisions collected by the CMS experiment and corresponding to an integrated luminosity of 36.3 fb−1. The measured distributions are consistent with the trends in the simulation that reveal two key features of the strong interaction: confinement and asymptotic freedom. By comparing the ratio of the measured three- and two-particle energy correlator distributions with theoretical calculations that resum collinear emissions at approximate next-to-next-to-leading-logarithmic accuracy matched to a next-to-leading-order calculation, the strong coupling is determined at the 𝑍 boson mass: 𝛼𝑆(𝑚𝑍)=0.1229+0.0040−0.0050, the most precise 𝛼𝑆(𝑚𝑍) value obtained using jet substructure observables.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Constraints on anomalous Higgs boson couplings from its production and decay using the WW channel in proton–proton collisions at sqrt{s} = 13 TeV
, The European Physical Journal C, Vol: 84A study of the anomalous couplings of the Higgs boson to vector bosons, including CP-violation effects, has been conducted using its production and decay in the WW channel. This analysis is performed on proton–proton collision data collected with the CMS detector at the CERN LHC during 2016–2018 at a center-of-mass energy of 13 TeV, and corresponds to an integrated luminosity of 138 fb¯¹. The different-flavor dilepton(eμ) final state is analyzed, with dedicated categories targeting gluon fusion, electroweak vector boson fusion, and associated production with a W or Z boson. Kinematic information from associated jets is combined using matrix element techniques to increase the sensitivity to anomalous effects at the production vertex. A simultaneous measurement of four Higgs boson couplings to electroweak vector bosons is performed in the framework of a standard model effective field theory. All measurements are consistent with the expectations for the standard model Higgs boson and constraints are set on the fractional contribution of the anomalous couplings to the Higgs boson production cross section.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Study of b-hadron decays to Λc+h−h′− final states
, Journal of High Energy Physics, Vol: 2024Decays of Ξ<inf>b</inf><sup>−</sup> and Ω<inf>b</inf><sup>−</sup> baryons to Λ<inf>c</inf><sup>+</sup>h<sup>−</sup>h<sup>′−</sup> final states, with h<sup>−</sup>h<sup>′−</sup> being π<sup>−</sup>π<sup>−</sup>, K<sup>−</sup>π<sup>−</sup> and K<sup>−</sup>K<sup>−</sup> meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7 fb<sup>−1</sup> of pp collisions collected at centre-of-mass energies s = 7, 8 and 13 TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B<sup>−</sup>→Λ<inf>c</inf><sup>+</sup>p¯π<sup>−</sup> mode, are measured, with Ξ<inf>b</inf><sup>−</sup>→Λ<inf>c</inf><sup>+</sup>K<sup>−</sup>π<sup>−</sup>, Ξ<inf>b</inf><sup>−</sup>→Λ<inf>c</inf><sup>+</sup>K<sup>−</sup>K<sup>−</sup> and Ω<inf>b</inf><sup>−</sup>→Λ<inf>c</inf><sup>+</sup>K<sup>−</sup>K<sup>−</sup> decays being observed at over 5 σ significance. The Ξ<inf>b</inf><sup>−</sup>→Λ<inf>c</inf><sup>+</sup>K<sup>−</sup>π<sup>−</sup> mode is also used to measure the Ξ<inf>b</inf><sup>−</sup> prod
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Journal articleAbed Abud A, Abi B, Acciarri R, et al., 2024,
Doping liquid argon with xenon in ProtoDUNE Single-Phase: effects on scintillation light
, Journal of Instrumentation, Vol: 19Doping of liquid argon TPCs (LArTPCs) with a small concentration of xenon is a technique for light-shifting and facilitates the detection of the liquid argon scintillation light. In this paper, we present the results of the first doping test ever performed in a kiloton-scale LArTPC. From February to May 2020, we carried out this special run in the single-phase DUNE Far Detector prototype (ProtoDUNE-SP) at CERN, featuring 720 t of total liquid argon mass with 410 t of fiducial mass. A 5.4 ppm nitrogen contamination was present during the xenon doping campaign. The goal of the run was to measure the light and charge response of the detector to the addition of xenon, up to a concentration of 18.8 ppm. The main purpose was to test the possibility for reduction of nonuniformities in light collection, caused by deployment of photon detectors only within the anode planes. Light collection was analysed as a function of the xenon concentration, by using the pre-existing photon detection system (PDS) of ProtoDUNE-SP and an additional smaller set-up installed specifically for this run. In this paper we first summarize our current understanding of the argon-xenon energy transfer process and the impact of the presence of nitrogen in argon with and without xenon dopant. We then describe the key elements of ProtoDUNE-SP and the injection method deployed. Two dedicated photon detectors were able to collect the light produced by xenon and the total light. The ratio of these components was measured to be about 0.65 as 18.8 ppm of xenon were injected. We performed studies of the collection efficiency as a function of the distance between tracks and light detectors, demonstrating enhanced uniformity of response for the anode-mounted PDS. We also show that xenon doping can substantially recover light losses due to contamination of the liquid argon by nitrogen.
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Journal articleLocke S, Coffani A, Abe K, et al., 2024,
New methods and simulations for cosmogenic induced spallation removal in Super-Kamiokande-IV
, Physical Review D, ISSN: 2470-0010Radioactivity induced by cosmic muon spallation is a dominant source of backgrounds for O(10 MeV) neutrino interactions in water Cherenkov detectors. In particular, it is crucial to reduce backgrounds to measure the solar neutrino spectrum and find neutrino interactions from distant supernovae. In this paper we introduce new techniques to locate muon-induced hadronic showers and efficiently reject spallation backgrounds. Applying these techniques to the solar neutrino analysis with an exposure of 2790×22.5 kton·day increases the signal efficiency by 12.6%, approximately corresponding to an additional year of detector running. Furthermore, we present the first spallation simulation at Super-Kamiokande, where we model hadronic interactions using fluka. The agreement between the isotope yields and shower pattern in this simulation and in the data gives confidence in the accuracy of this simulation, and thus opens the door to use it to optimize muon spallation removal in new data with gadolinium-enhanced neutron capture detection.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Search for prompt production of pentaquarks in charm hadron final states
, Physical Review D, Vol: 110, ISSN: 2470-0010A search for hidden-charm pentaquark states decaying to a range of ςcD¯ and Λc+D¯ final states, as well as doubly charmed pentaquark states to ςcD and Λc+D, is made using samples of proton-proton collision data corresponding to an integrated luminosity of 5.7 fb-1 recorded by the LHCb detector at s=13 TeV. Since no significant signals are found, upper limits are set on the pentaquark yields relative to that of the Λc+ baryon in the Λc+→pK-π+ decay mode. The known pentaquark states are also investigated, and their signal yields are found to be consistent with zero in all cases.
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Journal articleTofful A, Baynham CFA, Curtis EA, et al., 2024,
<SUP>171</SUP>Yb<SUP>+</SUP> optical clock with 2.2 x 10<SUP>-18</SUP> systematic uncertainty and absolute frequency measurements
, METROLOGIA, Vol: 61, ISSN: 0026-1394 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for new physics in high-mass diphoton events from proton-proton collisions at s = 13 TeV
, Journal of High Energy Physics, Vol: 2024Results are presented from a search for new physics in high-mass diphoton events from proton-proton collisions at s = 13 TeV. The data set was collected in 2016–2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb<sup>−1</sup>. Events with a diphoton invariant mass greater than 500 GeV are considered. Two different techniques are used to predict the standard model backgrounds: parametric fits to the smoothly-falling background and a first-principles calculation of the standard model diphoton spectrum at next-to-next-to-leading order in perturbative quantum chromodynamics calculations. The first technique is sensitive to resonant excesses while the second technique can identify broad differences in the invariant mass shape. The data are used to constrain the production of heavy Higgs bosons, Randall-Sundrum gravitons, the large extra dimensions model of Arkani-Hamed, Dimopoulos, and Dvali (ADD), and the continuum clockwork mechanism. No statistically significant excess is observed. The present results are the strongest limits to date on ADD extra dimensions and RS gravitons with a coupling parameter greater than 0.1.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Amplitude analysis and branching fraction measurement of B+→D∗−Ds+π+ decays
, Journal of High Energy Physics, Vol: 2024The decays of the B<sup>+</sup> meson to the final state D<sup>∗−</sup>D<inf>s</inf><sup>+</sup>π<sup>+</sup> are studied in proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb<sup>−1</sup>. The ratio of branching fractions of the B<sup>+</sup>→D<sup>∗−</sup>D<inf>s</inf><sup>+</sup>π<sup>+</sup> and B<sup>0</sup>→D<sup>∗−</sup>D<inf>s</inf><sup>+</sup> decays is measured to be 0.173 ± 0.006 ± 0.010, where the first uncertainty is statistical and the second is systematic. Using partially reconstructed D<inf>s</inf><sup>∗+</sup>→D<inf>s</inf><sup>+</sup>γ and D<inf>s</inf><sup>+</sup>π<sup>0</sup> decays, the ratio of branching fractions between the B<sup>+</sup>→D<sup>∗−</sup>D<inf>s</inf><sup>∗+</sup>π<sup>+</sup> and B<sup>+</sup>→D<sup>∗−</sup>D<inf>s</inf><sup>+</sup>π<sup>+</sup> decays is determined as 1.31 ± 0.07 ± 0.14. An amplitude analysis of the B<sup>+</sup>→D<sup>∗−</sup>D<inf>s</inf><sup>+</sup>π<sup>+</sup> decay is performed for the first time, revealing dominant contributions from known excited charm resonances decaying to the D<sup>*−</sup>π<sup>+</sup> final state. No significant evidence of exotic contributions in the D<inf>s</inf><sup>+</sup>π<sup>+</sup&
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for long-lived particles decaying in the CMS muon detectors in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 110, ISSN: 1550-2368A search for long-lived particles (LLPs) decaying in the CMS muon detectors is presented. A data sample of proton-proton collisions at √𝑠 =13 TeV corresponding to an integrated luminosity of 138 fb−1, recorded at the LHC in 2016–2018, is used. The decays of LLPs are reconstructed as high multiplicity clusters of hits in the muon detectors. In the context of twin Higgs models, the search is sensitive to LLP masses from 0.4 to 55 GeV and a broad range of LLP decay modes, including decays to hadrons, 𝜏 leptons, electrons, or photons. No excess of events above the standard model background is observed. The most stringent limits to date from LHC data are set on the branching fraction of the Higgs boson decay to a pair of LLPs with masses below 10 GeV. This search also provides the best limits for various intervals of LLP proper decay length and mass. Finally, this search sets the first limits at the LHC on a dark quantum chromodynamic sector whose particles couple to the Higgs boson through gluon, Higgs boson, photon, vector, and dark-photon portals, and is sensitive to branching fractions of the Higgs boson to dark quarks as low as 2 ×10−3.
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Journal articleAbed Abud A, Abi B, Acciarri R, et al., 2024,
The DUNE far detector vertical drift technology Technical design report
, Journal of Instrumentation, Vol: 19DUNE is an international experiment dedicated to addressing some of the questions at the forefront of particle physics and astrophysics, including the mystifying preponderance of matter over antimatter in the early universe. The dual-site experiment will employ an intense neutrino beam focused on a near and a far detector as it aims to determine the neutrino mass hierarchy and to make high-precision measurements of the PMNS matrix parameters, including the CP-violating phase. It will also stand ready to observe supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector implements liquid argon time-projection chamber (LArTPC) technology, and combines the many tens-of-kiloton fiducial mass necessary for rare event searches with the sub-centimeter spatial resolution required to image those events with high precision. The addition of a photon detection system enhances physics capabilities for all DUNE physics drivers and opens prospects for further physics explorations. Given its size, the far detector will be implemented as a set of modules, with LArTPC designs that differ from one another as newer technologies arise. In the vertical drift LArTPC design, a horizontal cathode bisects the detector, creating two stacked drift volumes in which ionization charges drift towards anodes at either the top or bottom. The anodes are composed of perforated PCB layers with conductive strips, enabling reconstruction in 3D. Light-trap-style photon detection modules are placed both on the cryostat's side walls and on the central cathode where they are optically powered. This Technical Design Report describes in detail the technical implementations of each subsystem of this LArTPC that, together with the other far detector modules and the near detector, will enable DUNE to achieve its physics goals.
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