Publications
1702 results found
Tumasyan 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: 0370-2693
A 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.
Tumasyan 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: 0370-2693
The 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.
Tumasyan 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: 0370-2693
The 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.
Tumasyan 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: 0370-2693
The 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.
Tumasyan 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 sqrt[s]=13 TeV., Phys Rev Lett, Vol: 131
We present the first direct search for exotic Higgs boson decays H→AA, A→γγ in events with two photonlike objects. The hypothetical particle A is a low-mass spin-0 particle decaying promptly to a merged diphoton reconstructed as a single photonlike object. We analyze the data collected by the CMS experiment at sqrt[s]=13 TeV corresponding to an integrated luminosity of 136 fb^{-1}. No excess above the estimated background is found. We set upper limits on the branching fraction B(H→AA→4γ) of (0.9-3.3)×10^{-3} at 95% confidence level for masses of A in the range 0.1-1.2 GeV.
Tumasyan 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: 2470-0010
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Proton reconstruction with the CMS-TOTEM Precision Proton Spectrometer, Journal of Instrumentation, Vol: 18, Pages: P09009-P09009
<jats:title>Abstract</jats:title> <jats:p>The Precision Proton Spectrometer (PPS) of the CMS and TOTEM experiments collected 107.7 fb<jats:sup>-1</jats:sup> in proton-proton (pp) collisions at the LHC at 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.</jats:p>
Hayrapetyan A, Tumasyan A, Adam W, et al., 2023, Observation of the Rare Decay of the η Meson to Four Muons., Phys Rev Lett, Vol: 131
A search for the rare η→μ^{+}μ^{-}μ^{+}μ^{-} double-Dalitz decay is performed using a sample of proton-proton collisions, collected by the CMS experiment at the CERN LHC with high-rate muon triggers during 2017 and 2018 and corresponding to an integrated luminosity of 101 fb^{-1}. A signal having a statistical significance well in excess of 5 standard deviations is observed. Using the η→μ^{+}μ^{-} decay as normalization, the branching fraction B(η→μ^{+}μ^{-}μ^{+}μ^{-})=[5.0±0.8(stat)±0.7(syst)±0.7(B_{2μ})]×10^{-9} is measured, where the last term is the uncertainty in the normalization channel branching fraction. This work achieves an improved precision of over 5 orders of magnitude compared to previous results, leading to the first measurement of this branching fraction, which is found to agree with theoretical predictions.
Tumasyan 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: 1434-6044
A 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.
Tumasyan 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: 131
The 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.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Measurement of the electroweak production of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>W</mml:mi><mml:mi>γ</mml:mi></mml:math> in association with two jets in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:math>, Physical Review D, Vol: 108, ISSN: 2470-0010
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Constraints on anomalous Higgs boson couplings to vector bosons and fermions from the production of Higgs bosons using the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi><mml:mi>τ</mml:mi></mml:math> final state, Physical Review D, Vol: 108, ISSN: 2470-0010
Tumasyan 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: 131
A 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.
Tumasyan 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, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 843, ISSN: 0370-2693
Results are presented of a search for a heavy Majorana neutrino [Formula presented] decaying into two same-flavor leptons ℓ (electrons or muons) and a quark-pair jet. A model is considered in which the [Formula presented] is an excited neutrino in a compositeness scenario. The analysis is performed using a sample of proton-proton collisions at s=13TeV recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 138fb−1. The data are found to be in agreement with the standard model prediction. For the process in which the [Formula presented] is produced in association with a lepton, followed by the decay of the [Formula presented] to a same-flavor lepton and a quark pair, an upper limit at 95% confidence level on the product of the cross section and branching fraction is obtained as a function of the [Formula presented] mass [Formula presented] and the compositeness scale Λ. For this model the data exclude the existence of [Formula presented] ([Formula presented]) for [Formula presented] below 6.0 (6.1) TeV, at the limit where [Formula presented] is equal to Λ. For [Formula presented], values of Λ less than 20 (23) TeV are excluded. These results represent a considerable improvement in sensitivity, covering a larger parameter space than previous searches in [Formula presented] collisions at 13 TeV.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for new physics using effective field theory in 13 TeV <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>p</mml:mi><mml:mi>p</mml:mi></mml:math> collision events that contain a top quark pair and a boosted <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Z</mml:mi></mml:math> or Higgs boson, Physical Review D, Vol: 108, ISSN: 2470-0010
Tumasyan A, Adam W, Bergauer T, et al., 2023, Azimuthal Correlations within Exclusive Dijets with Large Momentum Transfer in Photon-Lead Collisions., Phys Rev Lett, Vol: 131
The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization. This study uses a data sample of ultraperipheral lead-lead collisions at sqrt[s_{NN}]=5.02 TeV, corresponding to an integrated luminosity of 0.38 nb^{-1}, collected with the CMS experiment at the LHC. The measured second harmonic of the correlation between the sum and difference of the two jet transverse momentum vectors is found to be positive, and rising, as the dijet transverse momentum increases. A well-tuned model that has been successful at describing a wide range of proton scattering data from the HERA experiments fails to describe the observed correlations, suggesting the presence of gluon polarization effects.
Acar B, Adamov G, Adloff C, et al., 2023, Performance of the CMS High Granularity Calorimeter prototype to charged pion beams of 20–300 GeV/c, Journal of Instrumentation, Vol: 18, Pages: P08014-P08014
<jats:title>Abstract</jats:title> <jats:p>The upgrade of the CMS experiment for the high luminosity operation of the LHC comprises the replacement of the current endcap calorimeter by a high granularity sampling calorimeter (HGCAL). The electromagnetic section of the HGCAL is based on silicon sensors interspersed between lead and copper (or copper tungsten) absorbers. The hadronic section uses layers of stainless steel as an absorbing medium and silicon sensors as an active medium in the regions of high radiation exposure, and scintillator tiles directly read out by silicon photomultipliers in the remaining regions. As part of the development of the detector and its readout electronic components, a section of a silicon-based HGCAL prototype detector along with a section of the CALICE AHCAL prototype was exposed to muons, electrons and charged pions in beam test experiments at the H2 beamline at the CERN SPS in October 2018. The AHCAL uses the same technology as foreseen for the HGCAL but with much finer longitudinal segmentation. The performance of the calorimeters in terms of energy response and resolution, longitudinal and transverse shower profiles is studied using negatively charged pions, and is compared to GEANT4 predictions. This is the first report summarizing results of hadronic showers measured by the HGCAL prototype using beam test data.</jats:p>
Acar B, Adamov G, Adloff C, et al., 2023, Neutron irradiation and electrical characterisation of the first 8” silicon pad sensor prototypes for the CMS calorimeter endcap upgrade, Journal of Instrumentation, Vol: 18, Pages: P08024-P08024
<jats:title>Abstract</jats:title> <jats:p>As part of its HL-LHC upgrade program, the CMS collaboration is replacing its existing endcap calorimeters with a high-granularity calorimeter (CE). The new calorimeter is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic and hadronic compartments. Due to its compactness, intrinsic time resolution, and radiation hardness, silicon has been chosen as active material for the regions exposed to higher radiation levels. The silicon sensors are fabricated as 20 cm (8”) wide hexagonal wafers and are segmented into several hundred pads which are read out individually. As part of the sensor qualification strategy, 8” sensor irradiation with neutrons has been conducted at the Rhode Island Nuclear Science Center (RINSC) and followed by their electrical characterisation in 2020-21. The completion of this important milestone in the CE's R&D program is documented in this paper and it provides detailed account of the associated infrastructure and procedures. The results on the electrical properties of the irradiated CE silicon sensors are presented.</jats:p>
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks., Phys Rev Lett, Vol: 131
A search for nonresonant Higgs boson (H) pair production via gluon and vector boson (V) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb^{-1} collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic VVHH couplings, κ_{2V}, excluding κ_{2V}=0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for Higgs Boson and Observation of Z Boson through Their Decay into a Charm Quark-Antiquark Pair in Boosted Topologies in Proton-Proton Collisions at sqrt[s]=13 TeV., Phys Rev Lett, Vol: 131
A search for the standard model (SM) Higgs boson (H) produced with transverse momentum (p_{T}) greater than 450 GeV and decaying to a charm quark-antiquark (cc[over ¯]) pair is presented. The search is performed using proton-proton collision data collected at sqrt[s]=13 TeV by the CMS experiment at the LHC, corresponding to an integrated luminosity of 138 fb^{-1}. Boosted H→cc[over ¯] decay products are reconstructed as a single large-radius jet and identified using a deep neural network charm tagging technique. The method is validated by measuring the Z→cc[over ¯] decay process, which is observed in association with jets at high p_{T} for the first time with a signal strength of 1.00_{-0.14}^{+0.17}(syst)±0.08(theo)±0.06(stat), defined as the ratio of the observed process rate to the SM expectation. The observed (expected) upper limit on σ(H)B(H→cc[over ¯]) is set at 47 (39) times the SM prediction at 95% confidence level.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for direct pair production of supersymmetric partners of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math> leptons in the final state with two hadronically decaying <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>τ</mml:mi></mml:math> leptons and missing transverse momentum in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:math>, Physical Review D, Vol: 108, ISSN: 2470-0010
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for narrow resonances in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>b</mml:mi></mml:math>-tagged dijet mass spectrum in proton-proton collisions at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msqrt><mml:mi>s</mml:mi></mml:msqrt><mml:mo>=</mml:mo><mml:mn>13</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:math>, Physical Review D, Vol: 108, ISSN: 2470-0010
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for nonresonant Higgs boson pair production in final state with two bottom quarks and two tau leptons in proton-proton collisions at s=13 TeV, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
A search for the nonresonant production of Higgs boson pairs (HH ) via gluon-gluon and vector boson fusion processes in final states with two bottom quarks and two tau leptons is presented. The search uses data from proton-proton collisions at a center-of-mass energy of s=13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Events in which at least one tau lepton decays hadronically are considered and multiple machine learning techniques are used to identify and extract the signal. The data are found to be consistent, within uncertainties, with the standard model (SM) predictions. Upper limits on the HH production cross section are set to constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to 3.3 (5.2) times the SM prediction for the inclusive HH cross section and to 124 (154) times the SM prediction for the vector boson fusion HH cross section. At 95% confidence level, the Higgs field self-coupling is constrained to be within −1.7 and 8.7 times the SM expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within −0.4 and 2.6 times the SM expectation.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for electroweak production of charginos and neutralinos at s=13TeV in final states containing hadronic decays of WW, WZ, or WH and missing transverse momentum, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
This Letter presents a search for direct production of charginos and neutralinos via electroweak interactions. The results are based on data from proton-proton collisions at a center-of-mass energy of 13 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb−1. The search considers final states with large missing transverse momentum and pairs of hadronically decaying bosons WW, WZ, and WH, where H is the Higgs boson. These bosons are identified using novel algorithms. No significant excess of events is observed relative to the expectations from the standard model. Limits at the 95% confidence level are placed on the cross section for production of mass-degenerate wino-like supersymmetric particles χ˜1± and χ˜20, and mass-degenerate higgsino-like supersymmetric particles χ˜1±, χ˜20, and χ˜30. In the limit of a nearly-massless lightest supersymmetric particle χ˜10, wino-like particles with masses up to 870 and 960 GeV are excluded in the cases of χ˜20→Zχ˜10 and χ˜20→Hχ˜10, respectively, and higgsino-like particles are excluded between 300 and 650 GeV.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Precision measurement of the Z boson invisible width in pp collisions at s=13 TeV, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
A precise measurement of the invisible width of the Z boson produced in proton-proton collisions at a center-of-mass energy of 13 TeV is presented using data recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 36.3fb−1. The result is obtained from a simultaneous fit to kinematic distributions for two data samples of Z boson plus jets: one dominated by Z boson decays to invisible particles and the other by Z boson decays to muon and electron pairs. The invisible width is measured to be 523±3(stat)±16(syst)MeV. This result is the first precise measurement of the invisible width of the Z boson at a hadron collider, and is the single most precise direct measurement to date, competitive with the combined result of the direct measurements from the LEP experiments.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Measurement of the B<inf>s</inf><sup>0</sup>→μ<sup>+</sup>μ<sup>−</sup> decay properties and search for the B<sup>0</sup> → μ<sup>+</sup>μ<sup>−</sup> decay in proton-proton collisions at s=13TeV, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
Measurements are presented of the Bs0→μ+μ− branching fraction and effective lifetime, as well as results of a search for the B0→μ+μ− decay in proton-proton collisions at s=13TeV at the LHC. The analysis is based on data collected with the CMS detector in 2016–2018 corresponding to an integrated luminosity of 140fb−1. The branching fraction of the Bs0→μ+μ− decay and the effective Bs0 meson lifetime are the most precise single measurements to date. No evidence for the B0→μ+μ− decay has been found. All results are found to be consistent with the standard model predictions and previous measurements.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for a massive scalar resonance decaying to a light scalar and a Higgs boson in the four b quarks final state with boosted topology, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
We search for new massive scalar particles X and Y through the resonant process X→YH→bb¯bb¯, where H is the standard model Higgs boson. Data from CERN LHC proton-proton collisions are used, collected at a centre-of-mass energy of 13 TeV in 2016–2018 and corresponding to an integrated luminosity of 138fb−1. The search is performed in mass ranges of 0.9–4 TeV for X and 60–600 GeV for Y, where both Y and H are reconstructed as Lorentz-boosted single large-area jets. The results are interpreted in the context of the next-to-minimal supersymmetric standard model and also in an extension of the standard model with two additional singlet scalar fields. The 95% confidence level upper limits for the production cross section vary between 0.1 and 150 fb depending on the X and Y masses, and represent a significant improvement over results from previous searches.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Search for Higgs boson decays into Z and J/ψ and for Higgs and Z boson decays into J/ψ or Y pairs in pp collisions at s=13 TeV, Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, Vol: 842, ISSN: 0370-2693
Decays of the Higgs boson into a [Formula presented] boson and a [Formula presented] or [Formula presented] meson are searched for in four-lepton final states with the CMS detector at the LHC. A data set of proton-proton collisions corresponding to an integrated luminosity of 138fb−1 is used. Using the same data set, decays of the Higgs and [Formula presented] boson into quarkonium pairs are also searched for. An observation of such decays with this sample would indicate the presence of physics beyond the standard model. No evidence for these decays has been observed and upper limits at the 95% confidence level are placed on the corresponding branching fractions (B). Assuming longitudinal polarization of the Higgs boson decay products, 95% confidence level observed upper limits for [Formula presented] and [Formula presented] are 1.9×10−3 and 6.6×10−3, respectively.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Probing Heavy Majorana Neutrinos and the Weinberg Operator through Vector Boson Fusion Processes in Proton-Proton Collisions at sqrt[s]=13 TeV., Phys Rev Lett, Vol: 131
The first search exploiting the vector boson fusion process to probe heavy Majorana neutrinos and the Weinberg operator at the LHC is presented. The search is performed in the same-sign dimuon final state using a proton-proton collision dataset recorded at sqrt[s]=13 TeV, collected with the CMS detector and corresponding to a total integrated luminosity of 138 fb^{-1}. The results are found to agree with the predictions of the standard model. For heavy Majorana neutrinos, constraints on the squared mixing element between the muon and the heavy neutrino are derived in the heavy neutrino mass range 50 GeV-25 TeV; for masses above 650 GeV these are the most stringent constraints from searches at the LHC to date. A first test of the Weinberg operator at colliders provides an observed upper limit at 95% confidence level on the effective μμ Majorana neutrino mass of 10.8 GeV.
Tumasyan A, Adam W, Andrejkovic JW, et al., 2023, Measurements of Higgs boson production in the decay channel with a pair of $$\uptau $$ leptons in proton–proton collisions at $$\sqrt{s}=13$$ TeV, The European Physical Journal C, Vol: 83
<jats:title>Abstract</jats:title><jats:p>Measurements of Higgs boson production, where the Higgs boson decays into a pair of <jats:inline-formula><jats:alternatives><jats:tex-math>$$\uptau $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>τ</mml:mi> </mml:math></jats:alternatives></jats:inline-formula> leptons, are presented, using a sample of proton-proton collisions collected with the CMS experiment at a center-of-mass energy of "Equation missing"<!-- image only, no MathML or LaTex -->, corresponding to an integrated luminosity of 138<jats:inline-formula><jats:alternatives><jats:tex-math>$$\,\text {fb}^{-1}$$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mspace /> <mml:msup> <mml:mtext>fb</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math></jats:alternatives></jats:inline-formula>. Three analyses are presented. Two are targeting Higgs boson production via gluon fusion and vector boson fusion: a neural network based analysis and an analysis based on an event categorization optimized on the ratio of signal over background events. These are complemented by an analysis targeting vector boson associated Higgs boson production. Results are presented in the form of signal strengths relative to the standard model predictions and products of cross sections and branching fraction to <jats:inline-formula><jats:alternatives><jats:tex-math>$$\upt
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.