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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Higher-order moments of the elliptic flow distribution in PbPb collisions at √<i>s</i><sub>NN</sub>=5.02 TeV
, 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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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Measurement of the Zboson production cross-section inp pcollisions at √s=5.02TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Production of η and<i> η'</i> mesons in<i> pp</i> and pPb collisions
, PHYSICAL REVIEW C, Vol: 109, ISSN: 2469-9985 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at ffiffi s p=13 TeV
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Improved Measurement of CP Violation Parameters in B0s → J=ψK plus K - Decays in the Vicinity of the φ(1020) Resonance
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleMondal N, Mazumdar D, Chatterjee S, et al., 2024,
Exploring complex magnetic phase transitions and magnetocaloric effect in the nanocrystalline Nd<inf>0.5</inf>Ca<inf>0.5</inf>MnO<inf>3</inf> compound
, Ceramics International, Vol: 50, Pages: 5594-5603, ISSN: 0272-8842In this article, we have investigated the temperature and magnetic field-induced complex magnetic phases and magnetocaloric properties of the nanocrystalline Nd0.5Ca0.5MnO3 (NCMO) compound in detail. The compound exhibits charge-ordered antiferromagnetic (CO-AFM) and charge-orbital-ordered antiferromagnetic (AFM) phases at TCO≃ 225 K and TN= 160 K respectively. At the intermediate temperature range, i.e. TN≤ T ≤ TCO, an unfamiliar magnetic state is present where the orbital ordering of manganese ions sets progressively. Both the short-range and zig-zag ordered ferromagnetic (FM) chains and an AFM phase coexist within this temperature window. The effect of magnetic field and temperature drastically modifies the fragile magnetic ground state and this change is also reflected in the magnetocaloric properties of the studied compound. At the low-temperature region, an inverse magnetocaloric effect (MCE) is noticed due to the kinetically arrested magnetic moments of the AFM phase. However, a conventional MCE is noticed in the high-temperature regime. The anomalous behavior of the MCE in the nanocrystalline NCMO compound is analyzed by considering the effect of the reduction of particle size and the meta-stable nature of the magnetic ground state. In addition, we have paid attention to the hysteretic losses associated with the first-order phase transition (FOPT) in order to estimate the magnetic cooling capacity for the material. These studies carry notable importance for the usefulness of nanocrystalline half-doped manganite compounds not only for basic scientific research purpose, but also having possible practical utilization in the magnetic refrigeration industries.
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Journal articleDatta A, Mazumdar D, Banerjee S, et al., 2024,
Magnetic, magnetocaloric and critical behavior studies in Heusler compounds Co<inf>2-x</inf>Cr<inf>1+x</inf>Al
, Journal of Magnetism and Magnetic Materials, Vol: 591, ISSN: 0304-8853The polycrystalline Co2-xCr1+xAl (x = 0, 0.2, 0.4, 0.6, 0.8) compounds have been prepared successfully using the arc-melting technique. Room temperature XRD patterns indicate that all compounds have Heusler compound-like fcc structure along with B2 disorder. With the increasing Cr concentration within the compounds, the value of the lattice parameter increases. All compounds undergo a second-order paramagnetic (PM) to ferromagnetic (FM) transition and the value of PM-FM transition temperature (TC) decreases from 328 K to 134 K with increasing Cr concentration. For all compounds, the experimentally obtained value of MS is quite lower than the value of MS calculated from the well-known Slater-Pauling rule and the values of MS also decrease with increasing Cr concentration within the compounds. The magnetic entropy changes (ΔSM) and relative cooling power (RCP) for the Co2-xCr1+xAl (x = 0, 0.2, 0.4, 0.6) compounds have been calculated. The maximum magnetic entropy change (-ΔSMmax) and RCP both decrease with increasing the Cr concentration within the compounds. The values of critical exponents β, γ, δ associated with the magnetic phase transition have been estimated using the various well-established methods such as modified Arrott plot, power-law, Kouvel-Fisher methods and critical isotherm analysis for the Co2-xCr1+xAl (x = 0, 0.2, 0.4, 0.6) compounds. The obtained values of critical exponents, β and γ, for all compounds, do not follow any conventional universality class. Except for Co2CrAl (x = 0), the obtained β values for the other compounds (Cr-doped compounds) are quite higher than the highest β value among all theoretical models (the highest β value is 0.5 which belongs to the mean-field model). The high value of β occurs due to the Cr doping on the Co site in the system which creates disorder in the system. β>0.5 for all compounds, which indicates the long-range ordering below TC. The obtained
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Helium identification with LHCb
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2024,
Momentum scale calibration of the LHCb spectrometer
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleCalligaris L, Dell'Aquila CR, Bassi AVG, et al., 2024,
Novel developments on the OpenIPMC project
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleMehner T, Ardila-Perez LE, Balzer M, et al., 2024,
Lessons learned while developing the Serenity-S1 ATCA card
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Muon identification using multivariate techniques in the CMS experiment in proton-proton collisions at √s=13 TeV
, JOURNAL OF INSTRUMENTATION, Vol: 19, ISSN: 1748-0221 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of the Higgs boson production via vector boson fusion and its decay into bottom quarks in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAlbanese R, Alexandrov A, Alicante F, et al., 2024,
Measurement of the muon flux at the SND@LHC experiment
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at √s=13 TeV
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleAbratenko P, Alterkait O, Andrade AD, et al., 2024,
Search for Heavy Neutral Leptons in Electron-Positron and Neutral-Pion Final States with the MicroBooNE Detector
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Measurement of the τ lepton polarization in Z boson decays in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAccettura C, Adams D, Agarwal R, et al., 2024,
Towards a muon collider (vol 83, 864, 2023)
, EUROPEAN PHYSICAL JOURNAL C, Vol: 84, ISSN: 1434-6044 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2024,
Measurement of CP Violation in B^{0}→ψ(→ℓ^{+}ℓ^{-})K_{S}^{0}(→π^{+}π^{-}) Decays.
, Phys Rev Lett, Vol: 132A measurement of time-dependent CP violation in the decays of B^{0} and B[over ¯]^{0} mesons to the final states J/ψ(→μ^{+}μ^{-})K_{S}^{0}, ψ(2S)(→μ^{+}μ^{-})K_{S}^{0} and J/ψ(→e^{+}e^{-})K_{S}^{0} with K_{S}^{0}→π^{+}π^{-} is presented. The data correspond to an integrated luminosity of 6 fb^{-1} collected at a center-of-mass energy of sqrt[s]=13 TeV with the LHCb detector. The CP-violation parameters are measured to be S_{ψK_{S}^{0}}=0.717±0.013(stat)±0.008(syst) and C_{ψK_{S}^{0}}=0.008±0.012(stat)±0.003(syst). This measurement of S_{ψK_{S}^{0}} represents the most precise single measurement of the CKM angle β to date and is more precise than the current world average. In addition, measurements of the CP-violation parameters of the individual channels are reported and a combination with the LHCb Run 1 measurements is performed.
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Journal articleAad G, Abbott B, Abeling K, et al., 2024,
Evidence for the Higgs Boson Decay to a Z Boson and a Photon at the LHC
, PHYSICAL REVIEW LETTERS, Vol: 132, ISSN: 0031-9007 -
Journal articleSakai S, Abe K, Bronner C, et al., 2024,
Measurement of the neutrino-oxygen neutral-current quasielastic cross section using atmospheric neutrinos in the SK-Gd experiment
, PHYSICAL REVIEW D, Vol: 109, ISSN: 2470-0010 -
Journal articleKarikar A, Das K, Das I, 2024,
Magnetocaloric effect in nanocrystalline Sm<inf>0.5</inf>Ca<inf>0.15</inf>Sr<inf>0.35</inf>MnO<inf>3</inf>Compounds: Enhancement of relative cooling power
, Solid State Communications, Vol: 377, ISSN: 0038-1098This study explores the magnetic and Magnetocaloric Effect (MCE) in nanocrystalline Sm0.5Ca0.15Sr0.35MnO3 compounds, with a focus on enhancing the Relative Cooling Power (RCP). Our study indicates that the physical properties get drastically modified due to the reduction of the particle sizes. By investigating the impact of grain size on the MCE and RCP, this research aims to optimize cooling efficiency. The findings highlight the potential of doped manganite nanocrystalline materials as cost effective and environmentally friendly alternatives for advanced cooling technologies.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2024,
Study of charm hadronization with prompt Λc+ baryons in proton-proton and lead-lead collisions at sNN = 5.02 TeV
, Journal of High Energy Physics, Vol: 2024The production of prompt Λc+ baryons is measured via the exclusive decay channel Λc+→pK−π+ at a center-of-mass energy per nucleon pair of 5.02 TeV, using proton-proton (pp) and lead-lead (PbPb) collision data collected by the CMS experiment at the CERN LHC. The pp and PbPb data were obtained in 2017 and 2018 with integrated luminosities of 252 and 0.607 nb−1, respectively. The measurements are performed within the Λc+ rapidity interval |y| < 1 with transverse momentum (pT) ranges of 3–30 and 6–40 GeV/c for pp and PbPb collisions, respectively. Compared to the yields in pp collisions scaled by the expected number of nucleon-nucleon interactions, the observed yields of Λc+ with pT> 10 GeV/c are strongly suppressed in PbPb collisions. The level of suppression depends significantly on the collision centrality. The Λc+/D0 production ratio is similar in PbPb and pp collisions at pT> 10 GeV/c, suggesting that the coalescence process does not play a dominant role in prompt Λc+ baryon production at higher pT.
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Journal articleCMS Collaboration, 2024,
Measurement of the production cross section for a W boson in association with a charm quark in proton-proton collisions at s=13TeV.
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1434-6052The strange quark content of the proton is probed through the measurement of the production cross section for a W boson and a charm (c) quark in proton-proton collisions at a center-of-mass energy of 13TeV. The analysis uses a data sample corresponding to a total integrated luminosity of 138fb-1 collected with the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm jets are tagged using the presence of a muon or a secondary vertex inside the jet. The W+c production cross section and the cross section ratio Rc±=σ(W++c¯)/σ(W-+c) are measured inclusively and differentially as functions of the transverse momentum and the pseudorapidity of the lepton originating from the W boson decay. The precision of the measurements is improved with respect to previous studies, reaching 1% in Rc±=0.950±0.005(stat)±0.010(syst). The measurements are compared with theoretical predictions up to next-to-next-to-leading order in perturbative quantum chromodynamics.
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Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2024,
Luminosity determination using Z boson production at the CMS experiment
, European Physical Journal C: Particles and Fields, Vol: 84, ISSN: 1434-6044The measurement of Z boson production is presented as a method to determine the integrated luminosity of CMS data sets. The analysis uses proton–proton collision data, recorded by the CMS experiment at the CERN LHC in 2017 at a center-of-mass energy of 13 TeV. Events with Z bosons decaying into a pair of muons are selected. The total number of Z bosons produced in a fiducial volume is determined, together with the identification efficiencies and correlations from the same data set, in small intervals of f 20 pb−1 of integrated luminosity, thus facilitating the efficiency and rate measurement as a function of time and instantaneous luminosity. Using the ratio of the efficiency-corrected numbers of Z bosons, the precisely measured integrated luminosity of one data set is used to determine the luminosity of another. For the first time, a full quantitative uncertainty analysis of the use of Z bosons for the integrated luminosity measurement is performed. The uncertainty in the extrapolation between two data sets, recorded in 2017 at low and high instantaneous luminosity, is less than 0.5%. We show that the Z boson rate measurement constitutes a precise method, complementary to traditional methods, with the potential to improve the measurement of the integrated luminosity.
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Journal articleCMS Collaboration, 2024,
Constraints on anomalous Higgs boson couplings from its production and decay using the WW channel in proton-proton collisions at s = 13 TeV.
, Eur Phys J C Part Fields, Vol: 84, ISSN: 1434-6044A 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 ( e μ ) 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 articleCMSCollaboration, Hayrapetyan A, Tumasyan A, et al., 2024,
Observation of the Λ b 0 → J / ψ Ξ - K + decay.
, Eur Phys J C Part Fields, Vol: 84, ISSN: 1434-6044Using proton-proton collision data corresponding to an integrated luminosity of 140 fb - 1 collected by the CMS experiment at s = 13 Te V , the Λ b 0 → J / ψ Ξ - K + decay is observed for the first time, with a statistical significance exceeding 5 standard deviations. The relative branching fraction, with respect to the Λ b 0 → ψ ( 2 S ) Λ decay, is measured to be B ( Λ b 0 → J / ψ Ξ - K + ) / B ( Λ b 0 → ψ ( 2 S ) Λ ) = [ 3.38 ± 1.02 ± 0.61 ± 0.03 ] % , where the first uncertainty is statistical, the second is systematic, and the third is related to the uncertainties in B ( ψ ( 2 S ) → J / ψ π + π - ) and B ( Ξ - → Λ π - ) .
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Journal articleCMS Collaboration, Hayrapetyan A, Tumasyan A, et al., 2024,
Portable Acceleration of CMS Computing Workflows with Coprocessors as a Service.
, Comput Softw Big Sci, Vol: 8Computing demands for large scientific experiments, such as the CMS experiment at the CERN LHC, will increase dramatically in the next decades. To complement the future performance increases of software running on central processing units (CPUs), explorations of coprocessor usage in data processing hold great potential and interest. Coprocessors are a class of computer processors that supplement CPUs, often improving the execution of certain functions due to architectural design choices. We explore the approach of Services for Optimized Network Inference on Coprocessors (SONIC) and study the deployment of this as-a-service approach in large-scale data processing. In the studies, we take a data processing workflow of the CMS experiment and run the main workflow on CPUs, while offloading several machine learning (ML) inference tasks onto either remote or local coprocessors, specifically graphics processing units (GPUs). With experiments performed at Google Cloud, the Purdue Tier-2 computing center, and combinations of the two, we demonstrate the acceleration of these ML algorithms individually on coprocessors and the corresponding throughput improvement for the entire workflow. This approach can be easily generalized to different types of coprocessors and deployed on local CPUs without decreasing the throughput performance. We emphasize that the SONIC approach enables high coprocessor usage and enables the portability to run workflows on different types of coprocessors.
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Journal articleCMS Collaboration, 2024,
Measurement of multijet azimuthal correlations and determination of the strong coupling in proton-proton collisions at s = 13 Te V.
, Eur Phys J C Part Fields, Vol: 84, ISSN: 1434-6044A measurement is presented of a ratio observable that provides a measure of the azimuthal correlations among jets with large transverse momentum p T . This observable is measured in multijet events over the range of p T = 360 - 3170 Ge V based on data collected by the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 Te V , corresponding to an integrated luminosity of 134 fb - 1 . The results are compared with predictions from Monte Carlo parton-shower event generator simulations, as well 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 α S ( m Z ) = 0.1177 ± 0.0013 (exp) - 0.0073 + 0.0116 (theo) = 0 . 1177 - 0.0074 + 0.0117 , where the total uncertainty is dominated by the scale dependence of the fixed-order predictions. A test of the running of α S in the Te V region shows no deviation from the expected NLO pQCD behaviour.
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