WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/2

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Now showing 1 - 20 of 37

Citation - WoS: 15
Citation - Scopus: 24
Constraints on Anomalous Higgs Boson Couplings To Vector Bosons and Fermions From the Production of Higgs Bosons Using the Tt Final State
(Amer Physical Soc, 2023) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın
A study of anomalous couplings of the Higgs boson to vector bosons and fermions is presented. The data were recorded by the CMS experiment at a center-of-mass energy of pp collisions at the LHC of 13 TeV and correspond to an integrated luminosity of 138 fb-1. The study uses Higgs boson candidates produced mainly in gluon fusion or electroweak vector boson fusion at the LHC that subsequently decay to a pair of z leptons. Matrix-element and machine-learning techniques were employed in a search for anomalous interactions. The results are combined with those from the four-lepton and two-photon decay channels to yield the most stringent constraints on anomalous Higgs boson couplings to date. The pure CP-odd scenario of the Higgs boson coupling to gluons is excluded at 2.4 standard deviations. The results are consistent with the standard model predictions.
Citation - WoS: 1
Citation - Scopus: 2
Energy-Scaling Behavior of Intrinsic Transverse-Momentum Parameters in Drell-Yan Simulation
(Amer Physical Soc, 2025) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Makarenko, V.
An analysis is presented based on models of the intrinsic transverse momentum (intrinsic k(T)) of partons in nucleons by studying the dilepton transverse momentum in Drell-Yan events. Using parameter tuning in event generators and existing data from fixed-target experiments and from hadron colliders, our investigation spans 3 orders of magnitude in center-of-mass energy and 2 orders of magnitude in dilepton invariant mass. The results show an energy-scaling behavior of the intrinsic k(T) parameters, independent of the dilepton invariant mass at a given center-of-mass energy.
Citation - WoS: 37
Citation - Scopus: 59
Inclusive Nonresonant Multilepton Probes of New Phenomena at Root S=13 Tev
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Güler, Yalçın; The CMS Collaboration
An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying tau leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb(-1) of proton-proton collisions at root s = 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vectorlike tau lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vectorlike doublet model, these constraints are the most stringent to date. For the vectorlike singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations.
Citation - WoS: 61
Citation - Scopus: 68
Measurement of Differential T(t)over-Bar Production Cross Sections in the Full Kinematic Range Using Lepton Plus Jets Events From Proton-Proton Collisions at Root S=13 Tev
(Amer Physical Soc, 2021) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın; The CMS Collaboration
Measurements of differential and double-differential cross sections of top-quark pair (t (t) over bar) production arc presented in the lepton + jets channels with a single electron or muon and jets in the final state. The analysis combines for the first time signatures of top quarks with low transverse momentum p(T), where the top-quark decay products can be identified as separated jets and isolated leptons, and with high p(T), where the decay products are collimated and overlap. The measurements arc based on proton-proton collision data at is - = 13 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The cross sections are presented at the parton and particle levels, where the latter minimizes extrapolations based on theoretical assumptions. Most of the measured differential cross sections are well described by standard model predictions with the exception of some double-differential distributions. The inclusive t (t) over bar production cross section is measured to be sigma(t (t) over bar) = 791 +/- 25 pb, which constitutes the most precise measurement in the lepton + jets channel to date.
Citation - WoS: 16
Citation - Scopus: 36
Measurement of Energy Correlators Inside Jets and Determination of the Strong Coupling Α_s<
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Zhokin, A.
Energy correlators that describe energy-weighted distances between two or three particles in a hadronic jet are measured using an event sample of root s = 13 TeV proton-proton collisions collected by the CMS experiment and corresponding to an integrated luminosity of 36.3 fb(-1). The measured distributions are consistent with the trends in the simulation that reveal two key features of the strong interaction: confinement and asymptotic freedom. By comparing the ratio of the measured three- and two-particle energy correlator distributions with theoretical calculations that resum collinear emissions at approximate next-to-next-to-leading-logarithmic accuracy matched to a next-to-leading-order calculation, the strong coupling is determined at the Z boson mass: alpha(S)(m(Z)) = 0.1229(-0.0050)(+0.0040), the most precise alpha(S)(m(Z)) value obtained using jet substructure observables.
Citation - WoS: 5
Citation - Scopus: 26
Measurement of the Inclusive and Differential Higgs Boson Production Cross Sections in the Decay Mode To a Pair of Tau Leptons in Pp Collisions at Root S=13 Tev
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
Measurements of the inclusive and differential fiducial cross sections of the Higgs boson are presented, using the tau lepton decay channel. The differential cross sections are measured as functions of the Higgs boson transverse momentum, jet multiplicity, and transverse momentum of the leading jet in the event, if any. The analysis is performed using proton-proton collision data collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 138 fb-1. These are the first differential measurements of the Higgs boson cross section in the final state of two tau leptons. In final states with a large jet multiplicity or with a Lorentz-boosted Higgs boson, these measurements constitute a significant improvement over measurements performed in other final states.
Citation - WoS: 10
Citation - Scopus: 16
Measurement of the Production Cross Section for Z Plus B Jets in Proton-Proton Collisions at Root S=13 Tev
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Güler, Yalçın; The CMS Collaboration
The measurement of the cross section for the production of a Z boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet is performed with proton-proton collision data at p1/4 13 TeV. The data sample corresponds to an integrated luminosity of 137 fb-1, collected by the CMS experiment at the LHC during 2016???2018. The integrated cross sections for Z?? > 1 b jet and Z?? > 2 b jets are reported for the electron, muon, and combined channels. The fiducial cross sections in the combined channel are 6.52 ??? 0.04??stat?? ??? 0.40??syst?? ??? 0.14??theo?? pb for Z?? > 1 b jet and 0.65 ??? 0.03??stat?? ??? 0.07??syst?? ??? 0.02??theo?? pb for Z?? > 2 b jets. The differential cross section distributions are measured as functions of various kinematic observables that are useful for precision tests of perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections for Z?? > 2b jets and Z?? > 1 b jet processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 ??? 0.005??stat?? ??? 0.007??syst?? ??? 0.003??theo??. All measurements are compared with predictions from various event generators.
Citation - WoS: 19
Measurement of W-+/-gamma Differential Cross Sections in Proton-Proton Collisions at Root S=13 Tev and Effective Field Theory Constraints
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
Differential cross section measurements of W(+/-)y production in proton-proton collisions at root s = 13 TeV are presented. The data set used in this study was collected with the CMS detector at the CERN LHC in 2016-2018 with an integrated luminosity of 138 fb(-1). Candidate events containing an electron or muon, a photon, and missing transverse momentum are selected. The measurements are compared with standard model predictions computed at next-to-leading and next-to-next-to-leading orders in perturbative quantum chromodynamics. Constraints on the presence of TeV-scale new physics affecting the WW gamma vertex are determined within an effective field theory framework, focusing on the O-3w operator. A simultaneous measurement of the photon transverse momentum and the azimuthal angle of the charged lepton in a special reference frame is performed. This two-dimensional approach provides up to a factor of ten more sensitivity to the interference between the standard model and the O-3w contribution than using the transverse momentum alone.
Citation - WoS: 22
Citation - Scopus: 20
Measurements of Polarization and Spin Correlation and Observation of Entanglement in Top Quark Pairs Using Lepton Plus Jets Events From Proton-Proton Collisions at √s=13 Tev
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Benato, L.; Bergauer, T.; Druzhkin, D.
Measurements of the polarization and spin correlation in top quark pairs (t (t) over bar) are presented using events with a single electron or muon and jets in the final state. The measurements are based on proton-proton collision data from the LHC at root s = 13 TeV collected by the CMS experiment, corresponding to an integrated luminosity of 138 fb(-1). All coefficients of the polarization vectors and the spin correlation matrix are extracted simultaneously by performing a binned likelihood fit to the data. The measurement is performed inclusively and in bins of additional observables, such as the mass of the t (t) over bar system and the top quark scattering angle in the t (t) over bar rest frame. The measured polarization and spin correlation are in agreement with the standard model. From the measured spin correlation, conclusions on the t (t) over bar spin entanglement are drawn by applying the Peres-Horodecki criterion. The standard model predicts entangled spins for t (t) over bart states at the production threshold and at high masses of the t (t) over bart system. Entanglement is observed for the first time in events at high t (t) over bar mass, where a large fraction of the t (t) over bar decays are spacelike separated, with an expected and observed significance of above 5 standard deviations.
Citation - WoS: 15
Citation - Scopus: 21
Measurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at Root S=5.02 Tev Using Leptonic Decays
(Amer Physical Soc, 2021) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Gürpınar Güler, Emine; Güler, Yalçın; The CMS Collaboration
The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb(-1). Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as sigma(WW) = 37:0(-5.2)(+5.5) (stat)(-2.6)(+2.7) (syst) pb, sigma(WZ) = 6.4(-2.1)(+2.5) (stat)(-0.3)(+0.5)(syst) pb, and sigma(ZZ) = 5.3(-2.1)(+2.5)(stat)(-0.4)(+0.5) (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.
Citation - WoS: 3
Citation - Scopus: 4
Observation of Double j Meson Production in ppb Collisions at √s_{nn< Tev}
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Makarenko, V.
The first observation of the concurrent production of two J/psi mesons in proton-nucleus collisions is presented. The analysis is based on a proton-lead (pPb) data sample recorded at a nucleon-nucleon center-of-mass energy of 8.16 TeV by the CMS experiment at the CERN LHC and corresponding to an integrated luminosity of 174.6 nb(-1). The two J/psi mesons are reconstructed in their mu(+)mu(-) decay channels with transverse momenta p(T) > 6.5 GeV and rapidity vertical bar y vertical bar < 2.4. Events where one of the J/psi mesons is reconstructed in the dielectron channel are also considered in the search. The pPb -> J/psi J/psi +X process is observed with a significance of 5.3 standard deviations. The measured inclusive fiducial cross section, using the four-muon channel alone, is sigma(pPb (-> J/psi J/psi + X) = 22.0 +/- 8.9(stat) +/- 1.5(syst) nb. A fit of the data to the expected rapidity separation for pairs of J/psi mesons produced in single (SPS) and double (DPS) parton scatterings yields sigma(pPb)(SPS) (-> J/psi J/psi + X) = 16.5 +/- 10.8(stat) +/- 0.1(syst) nb and sigma(pPb)(DPS) (-> J/psi J/psi + X) = 5.4 +/- 6.2(stat) +/- 0.4(syst) nb, respectively. This latter result can he transformed into a lower hound on the effective DPS cross section, closely related to the squared average interparton transverse separation in the collision, of sigma(eff) > 1.0 mb at 95% confidence level.
Citation - WoS: 10
Citation - Scopus: 12
Observation of Enhanced Long-Range Elliptic Anisotropies Inside High-Multiplicity Jets in Pp Collisions at √s=13 Tev
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Zhokin, A.
A search for collective effects inside jets produced in proton-proton collisions is performed via correlation measurements of charged particles using the CMS detector at the CERN LHC. The analysis uses data collected at a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 138 fb(-1). Jets are reconstructed with the anti-kT algorithm with a distance parameter of 0.8 and are required to have transverse momentum greater than 550 GeV and pseudorapidity vertical bar eta(jet)vertical bar < 1.6. Two-particle correlations among the charged particles within the jets are studied as functions of the particles' azimuthal angle and pseudorapidity separations (Delta phi* and Delta eta*) in a jet coordinate basis, where particles' eta*, phi* are defined relative to the direction of the jet. The correlation functions are studied in classes of in-jet chargedparticle multiplicity up to N-ch(J) approximate to 100. Fourier harmonics are extracted from long-range azimuthal correlation functions to characterize azimuthal anisotropy for vertical bar Delta eta*vertical bar > 2. For low-N-ch(j) jets, the long-range elliptic anisotropic harmonic, v(2)*, is observed to decrease with N-ch(j). This trend is well described by Monte Carlo event generators. However, a rising trend for v(2)* emerges at N-ch(j) greater than or similar to 80, hinting at a possible onset of collective behavior, which is not reproduced by the models tested. This observation yields new insights into the dynamics of jet evolution in the vacuum.
Citation - WoS: 22
Citation - Scopus: 24
Observation of the B-C(+) Meson in Pb-Pb and Pp Collisions at Root S(nn)=5.02 Tev and Measurement of Its Nuclear Modification Factor
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
The B-c(+) meson is observed for the first time in heavy ion collisions. Data from the CMS detector are used to study the production of the B-c(+) meson in lead-lead (Pb-Pb) and proton-proton (pp) collisions at a center of-mass energy per nucleon pair of root s(NN) = 5.02 TeV, via the B-c(+) -> (J/psi -> mu(+)mu(-))mu(+)nu(mu) decay. The B-c(+) nuclear modification factor, derived from the Pb-Pb-to-pp ratio of production cross sections, is measured in two bins of the trimuon transverse momentum and of the Pb-Pb collision centrality. The B-c(+) meson is shown to be less suppressed than quarkonia and most of the open heavy-flavor mesons, suggesting that effects of the hot and dense nuclear matter created in heavy ion collisions contribute to its production. This measurement sets forth a promising new probe of the interplay of suppression and enhancement mechanisms in the production of heavy-flavor mesons in the quark-gluon plasma.
Observation of the Rare Decay of the Η Meson To Four Muons [2]
(Amer Physical Soc, 2023) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Gürpınar Güler, Emine; Güler, Yalçın
A search for the rare ri -> mu(+) mu(-) mu(+) mu(-) 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 eta -> mu+ mu(-) decay as normalization, the branching fraction B(eta -> mu(+) mu(-) mu(+) mu(-) = [5.0 +/- 0.8 (stat) +/- 0.7 (syst) +/- 0.7(B-2 mu)] x 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.
Citation - WoS: 2
Citation - Scopus: 3
Observation of the Ξb- → Ψ(2s)ξ- Decay and Studies of the Ξb(5945)0 Baryon in Proton-Proton Collisions at √s=13 Tev
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Lee, J.
The first observation of the decay Xi(-)(b) -> psi(2S)Xi(-) and measurement of the branching ratio of Xi(-)(b) -> psi(2S)Xi(-) to Xi(-)(b) -> J/psi Xi(-) are presented. The J/psi and psi(2S) mesons are reconstructed using their dimuon decay modes. The results are based on proton-proton colliding beam data from the LHC collected by the CMS experiment at root s = 13 TeV in 2016-2018, corresponding to an integrated luminosity of 140 fb(-1). The branching fraction ratio is measured to be B(Xi(-)(b) -> psi(2S)Xi(-))/B(Xi(-)(b) -> J/psi Xi(-)) = 0.84(-0.19)(+0.21)(stat) +/- 0.10(syst) +/- 0.02(B), where the last uncertainty comes from the uncertainties in the branching fractions of the charmonium states. New measurements of the Xi(b)(5945)(0) baryon mass and natural width are also presented, using the Xi(-)(b)pi(+) final state, where the Xi(-)(b) baryon is reconstructed through the decays J/psi Xi(-), psi(2S)Xi(-), J/psi Lambda K-, and J/psi Sigma K-0(-). Finally, the fraction of Xi(-)(b) baryons produced from Xi(b)(5945)(0) decays is determined.
Citation - WoS: 20
Citation - Scopus: 25
Precision Measurement of the W Boson Decay Branching Fractions in Proton-Proton Collisions at Root S=13 Tev
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
The leptonic and inclusive hadronic decay branching fractions of the W boson are measured using proton-proton collision data collected at p s = 13 TeV by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 35.9 fb???1. Events characterized by the production of one or two W bosons are selected and categorized based on the multiplicity and flavor of reconstructed leptons, the number of jets, and the number of jets identified as originating from the hadronization of b quarks. A binned maximum likelihood estimate of the W boson branching fractions is performed simultaneously in each event category. The measured branching fractions of the W boson decaying into electron, muon, and tau lepton final states are (10.83 ?? 0.10)%, (10.94 ?? 0.08)%, and (10.77 ?? 0.21)%, respectively, consistent with lepton flavor universality for the weak interaction. The average leptonic and inclusive hadronic decay branching fractions are estimated to be (10.89 ?? 0.08)% and (67.32 ?? 0.23)%, respectively. Based on the hadronic branching fraction, three standard model quantities are subsequently derived: the sum of squared elements in the first two rows of the Cabibbo???Kobayashi???Maskawa (CKM) matrix Pij IVijI2 = 1.984 ?? 0.021, the CKM element IVcsI = 0.967 ?? 0.011, and the strong coupling constant at the W boson mass scale, ??S(m2W) = 0.095 ?? 0.033.
Citation - WoS: 9
Citation - Scopus: 13
Probing Charm Quark Dynamics Via Multiparticle Correlations in Pb-Pb Collisions at Root S(nn)=5.02 Tev
(Amer Physical Soc, 2022) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Dragicevic, M.; Güler, Yalçın; The CMS Collaboration
Multiparticle azimuthal correlations of prompt D-0 mesons arc measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of root s(NN) = 5.02 TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (v(2)) of D-0 mesons as a function of event centrality and the D-0 transverse momentum. The ratios of the four-particle v(2) values to previously measured two-particle cumulant results provide direct experimental access to event-by-event fluctuations of charm quark azimuthal anisotropies. These ratios are also found to be comparable to those of inclusive charged particles in the event. However, hints of deviations are seen in the most central and peripheral collisions. To investigate the origin of flow fluctuations in the charm sector, these measurements are compared to a model implementing fluctuations of charm quark energy loss via collisional or radiative processes in the quark-gluon plasma. These models cannot quantitatively describe the data over the full transverse momentum and centrality ranges, although the calculations with collisional energy loss provide a better description of the data.
Citation - WoS: 3
Citation - Scopus: 10
Search for a Scalar or Pseudoscalar Dilepton Resonance Produced in Association With a Massive Vector Boson or Top Quark-Antiquark Pair in Multilepton Events at √s=13 Tev
(Amer Physical Soc, 2024) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Zhokin, A.
A search for beyond the standard model spin-0 bosons, phi, that decay into pairs of electrons, muons, or tau leptons is presented. The search targets the associated production of such bosons with a W or Z gauge boson, or a top quark-antiquark pair, and uses events with three or four charged leptons, including hadronically decaying tau leptons. The proton-proton collision data set used in the analysis was collected at the LHC from 2016 to 2018 at a center-of-mass energy of 13 TeV, and corresponds to an integrated luminosity of 138 fb(-1). The observations are consistent with the predictions from standard model processes. Upper limits are placed on the product of cross sections and branching fractions of such new particles over the mass range of 15 to 350 GeV with scalar, pseudoscalar, or Higgs-boson-like couplings, as well as on the product of coupling parameters and branching fractions. Several model-dependent exclusion limits are also presented. For a Higgs-boson-like phi model, limits are set on the mixing angle of the Higgs boson with the phi boson. For the associated production of a phi boson with a top quark-antiquark pair, limits are set on the coupling to top quarks. Finally, limits are set for the first time on a fermiophilic dilaton-like model with scalar couplings and a fermiophilic axion-like model with pseudoscalar couplings.
Citation - WoS: 2
Citation - Scopus: 5
Search for Bottom-Type Vectorlike Quark Pair Production in Dileptonic and Fully Hadronic Final States in Proton-Proton Collisions at √s=13 Tev
(Amer Physical Soc, 2024) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Zhokin, A.
A search is described for the production of a pair of bottom-type vectorlike quarks (B VLQs) with mass greater than 1000 GeV. Each B VLQ decays into a b quark and a Higgs boson, a b quark and a Z boson, or a t quark and a W boson. This analysis considers both fully hadronic final states and those containing a charged lepton pair from a Z boson decay. The products of the H -> bb boson decay and of the hadronic Z or W boson decays can be resolved as two distinct jets or merged into a single jet, so the final states are classified by the number of reconstructed jets. The analysis uses data corresponding to an integrated luminosity of 138 fb(-1) collected in proton-proton collisions at root s = 13 TeV with the CMS detector at the LHC from 2016 to 2018. No excess over the expected background is observed. Lower limits are set on the B VLQ mass at the 95% confidence level. These depend on the B VLQ branching fractions and are 1570 and 1540 GeV for 100% B -> bH and 100% B -> bZ, respectively. In most cases, the mass limits obtained exceed previous limits by at least 100 GeV.
Citation - WoS: 1
Citation - Scopus: 1
Search for Charged-Lepton Flavor Violation in the Production and Decay of Top Quarks Using Trilepton Final States in Proton-Proton Collisions at √s=13 Tev
(Amer Physical Soc, 2025) Hayrapetyan, A.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Chatterjee, S.; Zhokin, A.
A search is performed for charged-lepton flavor violating processes in top quark (t) production and decay. The data were collected by the CMS experiment from proton-proton collisions at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 138 fb(-1). The selected events are required to contain one opposite-sign electron-muon pair, a third charged lepton (electron or muon), and at least one jet of which no more than one is associated with a bottom quark. Boosted decision trees are used to distinguish signal from background, exploiting differences in the kinematics of the final states particles. The data are consistent with the standard model expectation. Upper limits at 95% confidence level are placed in the context of effective field theory on the Wilson coefficients, which range between 0.024-0.424 TeV-2 depending on the flavor of the associated light quark and the Lorentz structure of the interaction. These limits are converted to upper limits on branching fractions involving up (charm) quarks, t -> e mu u (t -> e mu c), of 0.032(0.498) x 10(-6), 0.022(0.369) x 10(-6), and 0.012(0.216) x 10(-6) for tensorlike, vectorlike, and scalarlike interactions, respectively.

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