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1.

001-es BibID:BIBFORM121299
035-os BibID:(WoS)001183209900005 (Scopus)85188217683
Első szerző:Tumasyan, Armen
Cím:Two-particle Bose-Einstein correlations and their Lévy parameters in PbPb collisions at root{s_NN} = 5.02 TeV / A. Tumasyan, CMS Collaboration
Dátum:2024
ISSN:2469-9985 2469-9993
Megjegyzések:Two-particle Bose-Einstein momentum correlation functions are studied for charged-hadron pairs in lead-lead collisions at a center-of-mass energy per nucleon pair of Formula Presented. The data sample, containing Formula Presented minimum bias events corresponding to an integrated luminosity of 0.607 Formula Presented, was collected by the CMS experiment in 2018. The experimental results are discussed in terms of a Lévy-type source distribution. The parameters of this distribution are extracted as functions of particle pair average transverse mass and collision centrality. These parameters include the Lévy index or shape parameter Formula Presented, the Lévy scale parameter Formula Presented, and the correlation strength parameter Formula Presented. The source shape, characterized by Formula Presented, is found to be neither Cauchy nor Gaussian, implying the need for a full Lévy analysis. Similarly to what was previously found for systems characterized by Gaussian source radii, a hydrodynamical scaling is observed for the Lévy Formula Presented parameter. The Formula Presented parameter is studied in terms of the core-halo model.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review C. - 109 : 2 (2024), p. 1-24. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Ujvári Balázs (1977-) (fizikus) Zilizi Gyula (1965-) (fizikus) CMS Collaboration
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2.

001-es BibID:BIBFORM120524
035-os BibID:(Scopus)85121314677 (WoS)000726017400004
Első szerző:Tumasyan, Armen
Cím:Measurement of differential t[overline]t production cross sections in the full kinematic range using lepton+jets events from proton-proton collisions at root{s} =13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2021
ISSN:2470-0010 2470-0029
Megjegyzések:Measurements of differential and double-differential cross sections of top-quark pair (t[overline]t) production are 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 are based on proton-proton collision data at root{s}=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[overline]t production cross section is measured to be [sigma]_t[overline]t=791 +/- 25 pb, which constitutes the most precise measurement in the lepton+jets channel to date.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 104 : 9 (2021), p. 1-93. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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3.

001-es BibID:BIBFORM120104
035-os BibID:(Scopus)85127560044 (WoS)000770948400001
Első szerző:Tumasyan, Armen
Cím:Measurement of W^+/-[gamma] differential cross sections in proton-proton collisions at root{s} = 13 TeV and effective field theory constraints / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések:Differential cross section measurements of W^+/-[gamma] 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.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 105 : 5 (2022), p. 1-34. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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4.

001-es BibID:BIBFORM119646
035-os BibID:(Scopus)85132573375 (WoS)000811587900005
Első szerző:Tumasyan, Armen
Cím:Measurement of the production cross section for Z+b jets in proton-proton collisions at root{s} =13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések: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 root{s}=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.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 105 : 9 (2022), p. 1-34. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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5.

001-es BibID:BIBFORM120521
035-os BibID:(Scopus)85123372703 (WoS)000746218600010
Első szerző:Tumasyan, Armen
Cím:Search for long-lived particles decaying in the CMS End Cap Muon Detectors in proton-proton collisions at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2021
ISSN:0031-9007
Megjegyzések:A search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons is presented. The data sample consists of 137 fb^-1 of proton-proton collisions at root{s}=13 TeV, recorded at the LHC in 2016-2018. A novel technique is employed to reconstruct decays of LLPs in the end cap muon detectors. The search is sensitive to a broad range of LLP decay modes and to masses as low as a few GeV. No excess of events above the SM background is observed. The most stringent limits to date on the branching fraction of the Higgs boson to LLPs subsequently decaying to quarks and [tau]^+[tau]^- are found for proper decay lengths greater than 6, 20, and 40 m, for LLP masses of 7, 15, and 40 GeV, respectively.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Charged particles
Data sample
Decay mode
End caps
Muon detectors
Novel techniques
Particle decay
Proton proton collisions
Standard-model Higgs bosons
Stringents
The standard model
Megjelenés:Physical Review Letters. - 127 : 26 (2021), p. 1-19. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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6.

001-es BibID:BIBFORM119485
035-os BibID:(Scopus)85133908962 (WoS)000830403500012
Első szerző:Tumasyan, Armen
Cím:Inclusive nonresonant multilepton probes of new phenomena at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések: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.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Proton-proton collisions
neutrino mass
scalar leptoquarks
underlying-event
pair production
lepton
search
fermion
number
quarks
Megjelenés:Physical Review D. - 105 : 11 (2022), p. 1-52. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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7.

001-es BibID:BIBFORM120084
035-os BibID:(Scopus)85130262791 (WoS)000810464600004
Első szerző:Tumasyan, Armen
Cím:Precision measurement of the W boson decay branching fractions in proton-proton collisions at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések:The leptonic and inclusive hadronic decay branching fractions of the W boson are measured using proton-proton collision data collected at root{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 [sigma]_{ij}|V_{ij}|^2 = 1.984+/-0.021, the CKM element |V_{cs}|=0.967+/-0.011, and the strong coupling constant at the W boson mass scale, [alfa]_s(m^W_2)=0.095+/-0.033.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 105 : 7 (2022), p. 1-31. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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8.

001-es BibID:BIBFORM119654
035-os BibID:(Scopus)85131676956 (WoS)000813239900002
Első szerző:Tumasyan, Armen
Cím:Search for invisible decays of the Higgs boson produced via vector boson fusion in proton-proton collisions at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések:A search for invisible decays of the Higgs boson produced via vector boson fusion (VBF) has been performed with 101 fb^-1 of proton-proton collisions delivered by the LHC at root{s} = 13 TeV and collected by the CMS detector in 2017 and 2018. The sensitivity to the VBF production mechanism is enhanced by constructing two analysis categories, one based on missing transverse momentum and a second based on the properties of jets. In addition to control regions with Z and W boson candidate events, a highly populated control region, based on the production of a photon in association with jets, is used to constrain the dominant irreducible background from the invisible decay of a Z boson produced in association with jets. The results of this search are combined with all previous measurements in the VBF topology, based on data collected in 2012 (at root{s}=8 TeV), 2015, and 2016, corresponding to integrated luminosities of 19.7, 2.3, and 36.3 fb^-1, respectively. The observed (expected) upper limit on the invisible branching fraction of the Higgs boson is found to be 0.18 (0.10) at the 95% confidence level, assuming the standard model production cross section. The results are also interpreted in the context of Higgs-portal models.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 105 : 9 (2022), p. 1-36. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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9.

001-es BibID:BIBFORM119466
Első szerző:Tumasyan, Armen
Cím: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 / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:0031-9007
Megjegyzések: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.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review Letters. - 128 : 25 (2022), p. 1-19. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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10.

001-es BibID:BIBFORM119457
035-os BibID:(WoS)000825415000002 (Scopus)85135447043
Első szerző:Tumasyan, Armen
Cím:Search for resonances decaying to three W bosons in the hadronic final state in proton-proton collisions at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések:A search for Kaluza-Klein excited vector boson resonances, WKK, decaying in cascade to three W bosons via a scalar radion R, WKK?WR?WWW, in a final state containing two or three massive jets is presented. The search is performed with s=13 TeV proton-proton collision data collected by the CMS experiment at the CERN LHC during 2016-2018, corresponding to an integrated luminosity of 138 fb-1. Two final states are simultaneously probed, one where the two W bosons produced by the R decay are reconstructed as separate, large-radius, massive jets, and one where they are merged into a single large-radius jet. The observed data are in agreement with the standard model expectations. Limits are set on the product of the WKK resonance cross section and branching fraction to three W bosons in an extended warped extra-dimensional model and are the first of their kind at the LHC.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 106 : 1 (2022), p. 1-33. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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11.

001-es BibID:BIBFORM119456
035-os BibID:(WoS)000828552400010 (Scopus)85135620132
Első szerző:Tumasyan, Armen
Cím:First Search for Exclusive Diphoton Production at High Mass with Tagged Protons in Proton-Proton Collisions at root{s} = 13 TeV / A. Tumasyan, CMS Collaboration, TOTEM Collaboration
Dátum:2022
ISSN:0031-9007
Megjegyzések:A search for exclusive two-photon production via photon exchange in proton-proton collisions, pp -> p gamma gamma p with intact protons, is presented. The data correspond to an integrated luminosity of 9.4 fb(-1) collected in 2016 using the CMS and TOTEM detectors at a center-of-mass energy of 13 TeVat the LHC. Events are selected with a diphoton invariant mass above 350 GeVand with both protons intact in the final state, to reduce backgrounds from strong interactions. The events of interest are those where the invariant mass and rapidity calculated from the momentum losses of the forward-moving protons match the mass and rapidity of the central, two-photon system. No events are found that satisfy this condition. Interpreting this result in an effective dimension-8 extension of the standard model, the first limits are set on the two anomalous four-photon coupling parameters. If the other parameter is constrained to its standard model value, the limits at 95% confidence level are vertical bar zeta(1)vertical bar < 2.9 x 10(-1)3 GeV-4 and vertical bar zeta(2)vertical bar < 6.0 x 10(-13) GeV-4.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review Letters. - 129 : 1 (2022), p. 1-20. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration TOTEM Collaboration
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12.

001-es BibID:BIBFORM119267
035-os BibID:(cikkazonosító)012004 (WoS)000990226700001 (Scopus)85136131307
Első szerző:Tumasyan, Armen
Cím:Search for heavy resonances decaying to Z([nu][nu])V(qq) in proton-proton collisions at root{s}=13 TeV / A. Tumasyan, CMS Collaboration
Dátum:2022
ISSN:2470-0010 2470-0029
Megjegyzések:A search is presented for heavy bosons decaying to Z(nu(nu) over bar )V(q (q) over bar'), where V can be a W or a Z boson. A sample of proton-proton collision data at root sp = 13 TeV was collected by the CMS experiment during 2016-2018. The data correspond to an integrated luminosity of 137 fb(-1). The event categorization is based on the presence of high-momentum jets in the forward region to identify production through weak vector boson fusion. Additional categorization uses jet substructure techniques and the presence of large missing transverse momentum to identify W and Z bosons decaying to quarks and neutrinos, respectively. The dominant standard model backgrounds are estimated using data taken from control regions. The results are interpreted in terms of radion, W' boson, and graviton models, under the assumption that these bosons are produced via gluon-gluon fusion, Drell-Yan, or weak vector boson fusion processes. No evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on various types of hypothetical new bosons. Observed (expected) exclusion limits on the masses of these bosons range from 1.2 to 4.0 (1.1 to 3.7) TeV.
Tárgyszavak:Természettudományok Fizikai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Physical Review D. - 106 : 1 (2022), p. 1-28. -
További szerzők:Bartók Márton (fizikus) Karancsi János (1987-) (fizikus) Raics Péter (1944-) (fizikus) Trócsányi Zoltán (1961-) (fizikus) Ujvári Balázs (1977-) (fizikus) CMS Collaboration
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