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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state in proton-proton collisions at s=13TeV
, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 844, ISSN: 0370-2693A search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state is presented. The analysis is based on proton-proton collision data recorded by the CMS detector in 2016–2018 at a centre-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 138 fb−1. The search is sensitive to resonances with masses between 1.3 and 6TeV, decaying to bosons that are highly Lorentz-boosted such that each of the bosons forms a single large-radius jet. Machine learning techniques are employed to identify such jets. No significant excess over the estimated standard model background is observed. A maximum local significance of 3.6 standard deviations, corresponding to a global significance of 2.3 standard deviations, is observed at masses of 2.1 and 2.9 TeV. In a heavy vector triplet model, spin-1 Z′ and W′ resonances with masses below 4.8TeV are excluded at the 95% confidence level (CL). These limits are the most stringent to date. In a bulk graviton model, spin-2 gravitons and spin-0 radions with masses below 1.4 and 2.7TeV, respectively, are excluded at 95% CL. Production of heavy resonances through vector boson fusion is constrained with upper cross section limits at 95% CL as low as 0.1 fb.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Evidence for four-top quark production in proton-proton collisions at s=13TeV
, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 844, ISSN: 0370-2693The production of four top quarks (tt¯tt¯) is studied with LHC proton-proton collision data samples collected by the CMS experiment at a center-of-mass energy of 13 TeV, and corresponding to integrated luminosities of up to 138fb−1. Events that have no leptons (all-hadronic), one lepton, or two opposite-sign leptons (where lepton refers only to prompt electrons or prompt muons) are considered. This is the first tt¯tt¯ measurement that includes the all-hadronic final state. The observed significance of the tt¯tt¯ signal in these final states of 3.9 standard deviations (1.5 expected) provides evidence for tt¯tt¯ production, with a measured cross section of 36−11+12fb. Combined with earlier CMS results in other final states, the signal significance is 4.0 standard deviations (3.2 expected). The combination returns an observed cross section of 17±4(stat)±3(syst)fb, which is consistent with the standard model prediction.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for medium effects using jets from bottom quarks in PbPb collisions at s<inf>NN</inf>=5.02TeV
, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 844, ISSN: 0370-2693The first study of the shapes of jets arising from bottom (b) quarks in heavy ion collisions is presented. Jet shapes are studied using charged hadron constituents as a function of their radial distance from the jet axis. Lead-lead (PbPb) collision data at a nucleon-nucleon center-of-mass energy of sNN=5.02TeV were recorded by the CMS detector at the LHC, with an integrated luminosity of 1.69nb−1. Compared to proton-proton collisions, a redistribution of the energy in b jets to larger distances from the jet axis is observed in PbPb collisions. This medium-induced redistribution is found to be substantially larger for b jets than for inclusive jets.
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Journal articleTumasyan A, Adam W, Bergauer T, et al., 2023,
Two-particle azimuthal correlations in γp interactions using pPb collisions at s<inf><inf>NN</inf></inf>=8.16TeV
, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 844, ISSN: 0370-2693The first measurements of the Fourier coefficients (VnΔ) of the azimuthal distributions of charged hadrons emitted from photon-proton (γp) interactions are presented. The data are extracted from 68.8 nb−1 of ultra-peripheral proton-lead (pPb) collisions at sNN=8.16TeV using the CMS detector. The high energy lead ions produce a flux of photons that can interact with the oncoming proton. This γp system provides a set of unique initial conditions with multiplicity lower than in photon-lead collisions but comparable to recent electron-positron and electron-proton data. The VnΔ coefficients are presented in ranges of event multiplicity and transverse momentum (pT) and are compared to corresponding hadronic minimum bias pPb results. For a given multiplicity range, the mean pT of charged particles is smaller in γp than in pPb collisions. For both the γp and pPb samples, V1Δ is negative, V2Δ is positive, and V3Δ consistent with 0. For each multiplicity and pT range, V2Δ is larger for γp events. The γp data are consistent with model predictions that have no collective effects.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for new physics in the τ lepton plus missing transverse momentum final state in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for a charged Higgs boson decaying into a heavy neutral Higgs boson and a W boson in proton-proton collisions at √<i>s</i>=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Measurement of differential cross sections for the production of a Z boson in association with jets in proton-proton collisions at √<i>s</i>=13 TeV
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Measurement of the Prompt. 22° Nuclear Modification. Factor in p-Pb Collisions at √SNN=8.16 TeV br
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Model-independent measurement of charm mixing parameters in B<overline><i> →</i> D0(→ K0Sπ+π- )μ-ν<overline>μX decays
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Exotic Higgs Boson Decays H → AA → 4γ with Events Containing Two Merged Diphotons in Proton-Proton Collisions at Vs=13 TeV
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleAbe K, Akhlaq N, Akutsu R, et al., 2023,
Measurements of neutrino oscillation parameters from the T2K experiment using 3.6 x 10<SUP>21</SUP> protons on target
, EUROPEAN PHYSICAL JOURNAL C, Vol: 83, ISSN: 1434-6044 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Observation of Same-Sign WW Production from Double Parton Scattering in Proton-Proton Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 131The first observation of the production of W^{±}W^{±} bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138 fb^{-1} recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7±11.2(stat) _{-8.6}^{+9.5}(syst)±12.1(model) fb, whereas the measured fiducial cross section is 6.28±0.81(stat)±0.69(syst)±0.37(model) fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.
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Journal articleSherrill N, Parsons AO, Baynham CFA, et al., 2023,
Analysis of atomic-clock data to constrain variations of fundamental constants
, NEW JOURNAL OF PHYSICS, Vol: 25, ISSN: 1367-2630 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2023,
Observation of the Rare Decay of the η Meson to Four Muons
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer
, Journal of Instrumentation, Vol: 18The Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb-1 in proton-proton (pp) collisions at theLHCat 13 TeV(Run 2). This paper describes the key features of the PPS alignment and optics calibrations, the proton reconstruction procedure, as well as the detector efficiency and the performance of the PPS simulation. The reconstruction and simulation are validated using a sample of (semi)exclusive dilepton events. The performance of PPS has proven the feasibility of continuously operating a near-beam proton spectrometer at a high luminosity hadron collider.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Reconstruction of decays to merged photons using end-to-end deep learning with domain continuation in the CMS detector
, Physical Review D, Vol: 108, ISSN: 2470-0010A novel technique based on machine learning is introduced to reconstruct the decays of highly Lorentz-boosted particles. Using an end-to-end deep learning strategy, the technique bypasses existing rule-based particle reconstruction methods typically used in high energy physics analyses. It uses minimally processed detector data as input and directly outputs particle properties of interest. The new technique is demonstrated for the reconstruction of the invariant mass of particles decaying in the CMS detector. The decay of a hypothetical scalar particle Formula Presented into two photons, Formula Presented, is chosen as a benchmark decay. Lorentz boosts Formula Presented are considered, ranging from regimes where both photons are resolved to those where the photons are closely merged as one object. A training method using domain continuation is introduced, enabling the invariant mass reconstruction of unresolved photon pairs in a novel way. The new technique is validated using Formula Presented decays in LHC collision data.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
A search for new physics in central exclusive production using the missing mass technique with the CMS detector and the CMS-TOTEM precision proton spectrometer
, European Physical Journal C, Vol: 83, ISSN: 1434-6044A generic search is presented for the associated production of a Z boson or a photon with an additional unspecified massive particle X, pp → pp + Z / γ + X , in proton-tagged events from proton–proton collisions at s=13TeV , recorded in 2017 with the CMS detector and the CMS-TOTEM precision proton spectrometer. The missing mass spectrum is analysed in the 600–1600 GeV range and a fit is performed to search for possible deviations from the background expectation. No significant excess in data with respect to the background predictions has been observed. Model-independent upper limits on the visible production cross section of pp → pp + Z / γ + X are set.
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Journal articleAraujo HM, Balashov SN, Borg JE, et al., 2023,
The MIGDAL experiment: Measuring a rare atomic process to aid the search for dark matter
, ASTROPARTICLE PHYSICS, Vol: 151, ISSN: 0927-6505- Author Web Link
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
First measurement of the top quark pair production cross section in proton-proton collisions at √<i>s</i>=13.6 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Measurement of the Time-Integrated CP Asymmetry in DKK Decays
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Measurement of the Branching Fractions B(B<SUP>0</SUP> → <i>p(p)over-barp(p)over-bar</i>) and <i>B</i>(<i>B<sub>s</sub><SUP>0</SUP></i> → <i>p(p)over-barp(p)over-bar</i>)
, PHYSICAL REVIEW LETTERS, Vol: 131, ISSN: 0031-9007 -
Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Observation of a Resonant Structure near the D_{s}^{+}D_{s}^{-} Threshold in the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} Decay.
, Phys Rev Lett, Vol: 131An amplitude analysis of the B^{+}→D_{s}^{+}D_{s}^{-}K^{+} decay is carried out to study for the first time its intermediate resonant contributions, using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A near-threshold peaking structure, referred to as X(3960), is observed in the D_{s}^{+}D_{s}^{-} invariant-mass spectrum with significance greater than 12 standard deviations. The mass, width, and the quantum numbers of the structure are measured to be 3956±5±10 MeV, 43±13±8 MeV, and J^{PC}=0^{++}, respectively, where the first uncertainties are statistical and the second systematic. The properties of the new structure are consistent with recent theoretical predictions for a state composed of cc[over ¯]ss[over ¯] quarks. Evidence for an additional structure is found around 4140 MeV in the D_{s}^{+}D_{s}^{-} invariant mass, which might be caused either by a new resonance with the 0^{++} assignment or by a J/ψϕ↔D_{s}^{+}D_{s}^{-} coupled-channel effect.
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Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Study of charmonium decays to <i>K</i><sub>S</sub><SUP>0</SUP><i>K</i>π in the <i>B</i> → (<i>K</i><sub>S</sub><SUP>0</SUP><i>K</i>π)<i>K</i> channels
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for Higgs Boson Decay to a Charm Quark-Antiquark Pair in Proton-Proton Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 131A search for the standard model Higgs boson decaying to a charm quark-antiquark pair, H→cc[over ¯], produced in association with a leptonically decaying V (W or Z) boson is presented. The search is performed with proton-proton collisions at sqrt[s]=13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb^{-1}. Novel charm jet identification and analysis methods using machine learning techniques are employed. The analysis is validated by searching for Z→cc[over ¯] in VZ events, leading to its first observation at a hadron collider with a significance of 5.7 standard deviations. The observed (expected) upper limit on σ(VH)B(H→cc[over ¯]) is 0.94 (0.50_{-0.15}^{+0.22})pb at 95% confidence level (C.L.), corresponding to 14 (7.6_{-2.3}^{+3.4}) times the standard model prediction. For the Higgs-charm Yukawa coupling modifier, κ_{c}, the observed (expected) 95% C.L. interval is 1.1<|κ_{c}|<5.5 (|κ_{c}|<3.4), the most stringent constraint to date.
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Journal articleAaij R, Abdelmotteleb ASW, Abellan Beteta C, et al., 2023,
Evidence for Modification of b Quark Hadronization in High-Multiplicity pp Collisions at sqrt[s]=13 TeV.
, Phys Rev Lett, Vol: 131The production rate of B_{s}^{0} mesons relative to B^{0} mesons is measured by the LHCb experiment in pp collisions at a center-of-mass energy sqrt[s]=13 TeV over the forward rapidity interval 2<y<4.5 as a function of the charged particle multiplicity measured in the event. Evidence at the 3.4σ level is found for an increase of the ratio of B_{s}^{0} to B^{0} cross sections with multiplicity at transverse momenta below 6 GeV/c, with no significant multiplicity dependence at higher transverse momentum. Comparison with data from e^{+}e^{-} collisions implies that the density of the hadronic medium may affect the production rates of B mesons. This is qualitatively consistent with the emergence of quark coalescence as an additional hadronization mechanism in high-multiplicity collisions.
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Journal articleTumasyan A, Adam W, Andrejkovic JW, et al., 2023,
Search for a heavy composite Majorana neutrino in events with dilepton signatures from proton-proton collisions at √s=13 Tev
, PHYSICS LETTERS B, Vol: 843, ISSN: 0370-2693 -
Journal articleHayrapetyan A, Tumasyan A, Adam W, et al., 2023,
Measurements of inclusive and differential cross sections for the Higgs boson production and decay to four-leptons in proton-proton collisions at √s=13 TeV
, JOURNAL OF HIGH ENERGY PHYSICS, ISSN: 1029-8479 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Search for <i>CP</i> violation using (T)over-cap-odd correlations in <i>B</i><SUP>0</SUP> → <i>p</i>(<i>p</i>)over-bar<i>K</i><SUP>+</SUP> π<SUP>-</SUP> decays
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Publisher Erratum: Open charm production and asymmetry in <i>p</i>Ne collisions at √<SUP>s</SUP>NN =68.5 GeV (vol 83, 541, 2023)
, EUROPEAN PHYSICAL JOURNAL C, Vol: 83, ISSN: 1434-6044 -
Journal articleAaij R, Abdelmotteleb ASW, Beteta CA, et al., 2023,
Multidifferential study of identified charged hadron distributions in Z-tagged jets in proton-proton collisions at v<i>s</i>=13 TeV
, PHYSICAL REVIEW D, Vol: 108, ISSN: 2470-0010
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