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Journal articleAbratenko P, Alterkait O, Andrade Aldana D, et al., 2024,
First Search for Dark-Trident Processes Using the MicroBooNE Detector.
, Phys Rev Lett, Vol: 132We present a first search for dark-trident scattering in a neutrino beam using a dataset corresponding to 7.2×10^{20} protons on target taken with the MicroBooNE detector at Fermilab. Proton interactions in the neutrino target at the main injector produce π^{0} and η mesons, which could decay into dark-matter (DM) particles mediated via a dark photon A^{'}. A convolutional neural network is trained to identify interactions of the DM particles in the liquid-argon time projection chamber (LArTPC) exploiting its imagelike reconstruction capability. In the absence of a DM signal, we provide limits at the 90% confidence level on the squared kinematic mixing parameter ϵ^{2} as a function of the dark-photon mass in the range 10≤M_{A^{'}}≤400 MeV. The limits cover previously unconstrained parameter space for the production of fermion or scalar DM particles χ for two benchmark models with mass ratios M_{χ}/M_{A^{'}}=0.6 and 2 and for dark fine-structure constants 0.1≤α_{D}≤1.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for the decay of the Higgs boson to a pair of light pseudoscalar bosons in the final state with four bottom quarks in proton-proton collisions at $$ \sqrt{\textrm{s}} $$ = 13 TeV
, Journal of High Energy Physics, Vol: 2024<jats:title>A<jats:sc>bstract</jats:sc></jats:title><jats:p>A search is presented for the decay of the 125 GeV Higgs boson (H) to a pair of new light pseudoscalar bosons (a), followed by the prompt decay of each a boson to a bottom quark-antiquark pair,<jats:inline-formula><jats:alternatives><jats:tex-math>$$ \textrm{H}\to \textrm{aa}\to \textrm{b}\overline{\textrm{b}}\textrm{b}\overline{\textrm{b}} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>H</mml:mi><mml:mo>→</mml:mo><mml:mi>aa</mml:mi><mml:mo>→</mml:mo><mml:mi>b</mml:mi><mml:mover><mml:mi>b</mml:mi><mml:mo>¯</mml:mo></mml:mover><mml:mi>b</mml:mi><mml:mover><mml:mi>b</mml:mi><mml:mo>¯</mml:mo></mml:mover></mml:math></jats:alternatives></jats:inline-formula>. The analysis is performed using a data sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb<jats:sup><jats:italic>−</jats:italic>1</jats:sup>. To reduce the background from standard model processes, the search requires the Higgs boson to be produced in association with a leptonically decaying W or Z boson. The analysis probes the production of new light bosons in a 15 <<jats:italic>m</jats:italic><jats:sub>a</jats:sub>< 60 GeV mass range. Assuming the standard model predictions for the Higgs boson production cross sections for pp → WH and ZH, model independent upper limits at 95% confidence level are derived for the branching fraction<jats:inline-formula><jats:alternatives><jats:tex-math>$$ \mathcal{B}\left(\textrm{H}\to \textrm{aa}\to \textrm{b}\overline{\textrm{b}}\textrm{b}\overl
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Modification of χ<sub><i>c</i>1</sub>(3872) and ψ(2<i>S</i>) Production in pPb Collisions at √<i>s</i><sub>NN</sub>=8.16 TeV
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for baryon number violation in top quark production and decay using proton-proton collisions at sqrt[s]=13 TeV
, Physical Review Letters, Vol: 132, ISSN: 0031-9007A search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138 fb−1. Candidate events are selected by requiring two oppositely charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark. Multivariate discriminants are used to separate the signal from the background. No significant deviation from the standard model prediction is observed. Upper limits are placed on the strength of baryon number violating couplings. For the first time the production of single top quarks via baryon number violating interactions is studied. This allows the search to set the most stringent constraints to date on the branching fraction of the top quark decay to a lepton, an up-type quark (𝑢 or 𝑐), and a down-type quark (𝑑, 𝑠, or 𝑏). The results improve the previous bounds by 3 to 6 orders of magnitude based on the fermion flavor combination of the baryon number violating interactions.
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Journal articleMarshall AM, Mccann MA, Patel M, et al., 2024,
Maximizing the physics potential of <i>B</i><SUP>±</SUP> <i>→</i> π<SUP>±</SUP> μ<SUP>+</SUP>μ<SUP>-</SUP> decays
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleAhmed A, Das K, Das I, 2024,
Large magnetocaloric effect and giant magnetoresistance in rare earth based intermetallic compound ErAl3: construction of magnetic phase diagram.
, J Phys Condens Matter, Vol: 36This study explores the magnetic and magnetotransport behavior of polycrystalline ErAl3compound. The polycrystalline compound adopts HoAl3-type structures with the R-3m space group, No. 166-2 and hR60 configurations. Multiple magnetic orderings and two field-induced metamagnetic transitions are observed. ErAl3exhibits a significant magnetocaloric effect (MCE),-ΔSM= 15.25 J kg-1K-1and high relative cooling power of 383 J kg-1with applied magnetic field change (ΔH) of 70 kOe near the paramagnetic to ferromagnetic transition, showcasing its potential for magnetic refrigeration technology. The compound also demonstrates metallic behavior, with a notable magnetoresistance of 48.5%at 2 K due to the suppression of antiferromagnetism. The magnetic phase diagram reveals four distinct phases influenced by temperature and magnetic field, identified through the study of the MCE.
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Journal articleMandal AK, Sarkar S, Chandra M, et al., 2024,
Navigating the magnetic contribution of the commonly used single-crystal substrates SrTiO<inf>3</inf> (100) and LaAlO<inf>3</inf> (100) in weak magnetic thin films
, Journal of Physics D: Applied Physics, Vol: 57, ISSN: 0022-3727In recent years, thin films of weak ferromagnetic materials have been in huge demand; however, probing their magnetic characteristics has been difficult due to contributions from underlying substrates. In the present study, we have analyzed the magnetic properties of the commonly used single-crystal SrTiO3 (100) and LaAlO3 (100) substrates and performed a time-dependent annealing protocol in vacuum and ambient oxygen pressure to mitigate the intrinsic weak ferromagnetic contributions from these substrates arising due to the presence of disorder or defects such as vacancies in the pristine substrates. It is shown that after proper air annealing, the substrate magnetic background becomes diamagnetic. When such air-annealed diamagnetic substrates are used for the deposition of low-thickness films carrying low magnetic moments such as SrRuO3 and SrMnO3 thin films, their magnetic transitions are explicitly observed. The proposed annealing protocols help to improve the signal from weak magnetic samples. This allows us to analyze the film’s magnetic properties without worrying about the contribution from the substrate.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Observation of Λ<i><sub>b</sub></i><SUP>0</SUP> → Λ<i><sub>c</sub></i><SUP>+</SUP> (<i>D</i>)over-bar<SUP>(</SUP>*<SUP>)0</SUP> <i>K</i><SUP>-</SUP> and Λ<i><sub>b</sub></i><SUP>0</SUP> → Λ<i><sub>c</sub></i><SUP>+</SUP> <i>D<sub>s</sub></i>*<SUP>-</SUP> decays
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleAhdida C, Akmete A, Albanese R, et al., 2024,
Reconstruction of 400 GeV/c proton interactions with the SHiP-charm project
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for pair production of scalar and vector leptoquarks decaying to muons and bottom quarks in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368A search for pair production of scalar and vector leptoquarks (LQs) each decaying to a muon and a bottom quark is performed using proton-proton collision data collected at √𝑠 =13 TeV with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 138 fb−1. No excess above standard model expectation is observed. Scalar (vector) LQs with masses less than 1810 (2120) GeV are excluded at 95% confidence level, assuming a 100% branching fraction of the LQ decaying to a muon and a bottom quark. These limits represent the most stringent to date.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Nonresonant central exclusive production of charged-hadron pairs in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368The central exclusive production of charged-hadron pairs in 𝑝𝑝 collisions at a center-of-mass energy of 13 TeV is examined, based on data collected in a special high-𝛽* run of the LHC. The nonresonant continuum processes are studied with the invariant mass of the centrally produced two-pion system in the resonance-free region, 𝑚𝜋+𝜋− <0.7 or 𝑚𝜋+𝜋− >1.8 GeV. Differential cross sections as functions of the azimuthal angle between the surviving protons, squared exchanged four-momenta, and 𝑚𝜋+𝜋− are measured in a wide region of scattered proton transverse momenta, between 0.2 and 0.8 GeV, and for pion rapidities |𝑦| <2. A rich structure of interactions related to double-pomeron exchange is observed. A parabolic minimum in the distribution of the two-proton azimuthal angle is observed for the first time. It can be interpreted as an effect of additional pomeron exchanges between the protons from the interference between the bare and the rescattered amplitudes. After model tuning, various physical quantities are determined that are related to the pomeron cross section, proton-pomeron and meson-pomeron form factors, pomeron trajectory and intercept, and coefficients of diffractive eigenstates of the proton.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Amplitude analysis of the Λb0→pK−γ decay
, Journal of High Energy Physics, Vol: 2024The resonant structure of the radiative decay Λb0→pK−γ in the region of proton-kaon invariant-mass up to 2.5 GeV/c2 is studied using proton-proton collision data recorded at centre-of-mass energies of 7, 8, and 13 TeV collected with the LHCb detector, corresponding to a total integrated luminosity of 9 fb−1. Results are given in terms of fit and interference fractions between the different components contributing to this final state. Only Λ resonances decaying to pK− are found to be relevant, where the largest contributions stem from the Λ(1520), Λ(1600), Λ(1800), and Λ(1890) states.
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Journal articleAalbers J, Akerib DS, Al Musalhi AK, et al., 2024,
New constraints on ultraheavy dark matter from the LZ experiment
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/𝑐2 to a few TeV/𝑐2. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a reanalysis of the first science run of the LZ experiment, with an exposure of 0.9 tonne×yr, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 1017 GeV/𝑐2.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for long-lived particles using displaced vertices and missing transverse momentum in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368A search for the production of long-lived particles in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC is presented. The search is based on data collected by the CMS experiment in 2016–2018, corresponding to a total integrated luminosity of 137 fb−1. This search is designed to be sensitive to long-lived particles with mean proper decay lengths between 0.1 and 1000 mm, whose decay products produce a final state with at least one displaced vertex and missing transverse momentum. A machine learning algorithm, which improves the background rejection power by more than an order of magnitude, is applied to improve the sensitivity. The observation is consistent with the standard model background prediction, and the results are used to constrain split supersymmetry (SUSY) and gauge-mediated SUSY breaking models with different gluino mean proper decay lengths and masses. This search is the first CMS search that shows sensitivity to hadronically decaying long-lived particles from signals with mass differences between the gluino and neutralino below 100 GeV. It sets the most stringent limits to date for split-SUSY models and gauge-mediated SUSY breaking models with gluino proper decay length less than 6 mm.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Combined search for electroweak production of winos, binos, higgsinos, and sleptons in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368A combination of the results of several searches for the electroweak production of the supersymmetric partners of standard model bosons, and of charged leptons, is presented. All searches use proton-proton collision data at √𝑠 =13 TeV recorded with the CMS detector at the LHC in 2016–2018. The analyzed data correspond to an integrated luminosity of up to 137 fb−1. The results are interpreted in terms of simplified models of supersymmetry. Two new interpretations are added with this combination: a model spectrum with the bino as the lightest supersymmetric particle together with mass-degenerate Higgsinos decaying to the bino and a standard model boson, and the compressed-spectrum region of a previously studied model of slepton pair production. Improved analysis techniques are employed to optimize sensitivity for the compressed spectra in the wino and slepton pair production models. The results are consistent with expectations from the standard model. The combination provides a more comprehensive coverage of the model parameter space than the individual searches, extending the exclusion by up to 125 GeV, and also targets some of the intermediate gaps in the mass coverage.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for stealth supersymmetry in final states with two photons, jets, and low missing transverse momentum in proton-proton collisions at √s=13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368he results of a search for stealth supersymmetry in final states with two photons and jets, targeting a phase space region with low missing transverse momentum (𝑝missT), are reported. The study is based on a sample of proton-proton collisions at √𝑠=13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb−1. As LHC results continue to constrain the parameter space of the minimal supersymmetric standard model, the low 𝑝missT regime is increasingly valuable to explore. To estimate the backgrounds due to standard model processes in such events, we apply corrections derived from simulation to an estimate based on a control selection in data. The results are interpreted in the context of simplified stealth supersymmetry models with gluino and squark pair production. The observed data are consistent with the standard model predictions, and gluino (squark) masses of up to 2150 (1850) GeV are excluded at the 95% confidence level.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Observation of the 𝐽/𝜓 →𝜇+𝜇−𝜇+𝜇− decay in proton-proton collisions at √𝑠 =13 TeV
, Physical Review D: Particles, Fields, Gravitation and Cosmology, Vol: 109, ISSN: 1550-2368The 𝐽/𝜓 →𝜇+𝜇−𝜇+𝜇− decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of 33.6 fb−1. Normalizing to the 𝐽/𝜓 →𝜇+𝜇− decay mode leads to a branching fraction of [10.1+3.3−2.7(stat) ±0.4(syst)] ×10−7, a value that is consistent with the standard model prediction.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for the lepton flavor violating τ → 3μ decay in proton-proton collisions at √s=13 TeV
, Physics Letters B: Nuclear Physics and Particle Physics, Vol: 853, ISSN: 0370-2693A search for the lepton flavor violating τ → 3μ decay is performed using proton-proton collision events at acenter-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2017–2018, corresponding to anintegrated luminosity of 97.7 fb−1. Tau leptons produced in both heavy-flavor hadron and W boson decays areexploited in the analysis. No evidence for the decay is observed. The results of this search are combined withan earlier null result based on data collected in 2016 to obtain a total integrated luminosity of 131 fb−1. Theobserved (expected) upper limits on the branching fraction (τ → 3μ) at confidence levels of 90 and 95% are2.9 × 10−8 (2.4 × 10−8) and 3.6 × 10−8 (3.0 × 10−8), respectively
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Journal articleAbend S, Allard B, Alonso I, et al., 2024,
Terrestrial very-long-baseline atom interferometry: workshop summary
, AVS Quantum Science, Vol: 6, ISSN: 2639-0213This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more kilometer--scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.
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Journal articleAbbaneo D, Ahmad S, Albanese R, et al., 2024,
Results and Perspectives from the First Two Years of Neutrino Physics at the LHC by the SND@LHC Experiment
, SYMMETRY-BASEL, Vol: 16 -
Journal articleBrown C, Spannowsky M, Tapper A, et al., 2024,
Quantum pathways for charged track finding in high-energy collisions
, Frontiers in Artificial Intelligence, Vol: 7, ISSN: 2624-8212In high-energy particle collisions, charged track finding is a complex yet crucial endeavor. We propose a quantum algorithm, specifically quantum template matching, to enhance the accuracy and efficiency of track finding. Abstracting the Quantum Amplitude Amplification routine by introducing a data register, and utilizing a novel oracle construction, allows data to be parsed to the circuit and matched with a hit-pattern template, without prior knowledge of the input data. Furthermore, we address the challenges posed by missing hit data, demonstrating the ability of the quantum template matching algorithm to successfully identify charged-particle tracks from hit patterns with missing hits. Our findings therefore propose quantum methodologies tailored for real-world applications and underline the potential of quantum computing in collider physics.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Search for a new resonance decaying into two spin-0 bosons in a final state with two photons and two bottom quarks in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for a third-generation leptoquark coupled to a τ lepton and a b quark through single, pair, and nonresonant production in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurements of the branching fraction ratio <i>B</i>(φ → μ<SUP>+</SUP>μ<SUP>-</SUP>)/<i>B</i>(φ → e<SUP>+</SUP>e<SUP>-</SUP>) with charm meson decays
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of associated Jψ-ψ(2S) production cross-section in pp collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
A measurement of ΔΓ<sub>s</sub>
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleArmano M, Audley H, Baird J, et al., 2024,
Nano-Newton electrostatic force actuators for femto-Newton-sensitive measurements: System performance test in the LISA Pathfinder mission
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleHenry S, Su H, Akhter S, et al., 2024,
Measurement of electron neutrino and antineutrino cross sections at low momentum transfer
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of the primary Lund jet plane density in proton-proton collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAalbers J, Akerib DS, Al Musalhi AK, et al., 2024,
First constraints on WIMP-nucleon effective field theory couplings in an extended energy region from LUX-ZEPLIN
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010
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