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Tétel Szabadon hozzáférhető Constraints on the pMSSM, AMSB model and on other models from the search for long-lived charged particles in proton–proton collisions at √s = 8 TeVKhachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; J. Karancsi; A. Makovec; P. Raics; Z. L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Makovec Alajos (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Debreceni EgyetemStringent limits are set on the long-lived lepton-like sector of the phenomenological minimal supersymmetric standard model (pMSSM) and the anomaly-mediated supersymmetry breaking (AMSB) model. The limits are derived from the results presented in a recent search for long-lived charged particles in proton–proton collisions, based on data collected by the CMS detector at a centre-of-mass energy of 8 TeV at the Large Hadron Collider. In the pMSSM parameter sub-space considered, 95.9 % of the points predicting charginos with a lifetime of at least 10 ns are excluded. These constraints on the pMSSM are the first obtained at the LHC. Charginos with a lifetime greater than 100 ns and masses up to about 800 GeV in the AMSB model are also excluded. The method described can also be used to set constraints on other models.Tétel Szabadon hozzáférhető Distributions of topological observables in inclusive three- and four-jet events in pp collisions at √S=7 TeVKhachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; J. Karancsi; A. Makovec; P. Raics; Z. L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Makovec Alajos (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Debreceni EgyetemThis paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7$$\,\text {TeV}$$TeV with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1$$\,\text {fb}^{-1}$$fb-1. The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with pythia6 displays the overall best agreement withdata.Tétel Szabadon hozzáférhető Measurement of differential top-quark-pair production cross sections in pp collisions at √s = 7TeVChatrchyan S.; Khachatryan V.; Sirunyan A.M.; J. Karancsi; P. Raics; Z.L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Debreceni EgyetemNormalised differential top-quark-pair production cross sections are measured in pp collisions at a centre-of-mass energy of 7 TeVat the LHC with the CMS detector using data recorded in 2011 corresponding to an integrated luminosity of 5. 0 fb-1. The measurements are performed in the lepton+jets decay channels (e+jets and μ+jets) and the dilepton decay channels (e+}e-, μ+μ-, and μ±e∓). The tt̄ differential cross section is measured as a function of kinematic properties of the final-state charged leptons and jets associated to b quarks, as well as those of the top quarks and the tt̄ system. The data are compared with several predictions from perturbative QCD calculations up to approximate next-to-next-to-leading-order precision. No significant deviations from the standard model are observed.Tétel Szabadon hozzáférhető Measurement of Long-Range Near-Side Two-Particle Angular Correlations in pp Collisions at s =13 TeVKhachatryan V.; Sirunyan A.M.; Tumasyan A.; J. Karancsi; M. Bartók; A. Makovec; P. Raics; Z. L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Bartók Márton (2024-) (xxx); Makovec Alajos (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Fizikai Intézet -- 749; TTK; Debreceni EgyetemResults on two-particle angular correlations for charged particles produced in pp collisions at a center-of-mass energy of 13 TeV are presented. The data were taken with the CMS detector at the LHC and correspond to an integrated luminosity of about 270 nb-1. The correlations are studied over a broad range of pseudorapidity (|η|<2.4) and over the full azimuth (φ) as a function of charged particle multiplicity and transverse momentum (pT). In high-multiplicity events, a long-range (|Δη|>2.0), near-side (Δφ≈0) structure emerges in the two-particle Δη-Δφ correlation functions. The magnitude of the correlation exhibits a pronounced maximum in the range 1.0Tétel Szabadon hozzáférhető Measurement of the inclusive jet cross section in pp collisions at √s = 2.76 TeVV. Khachatryan; A. M. Sirunyan; A. Tumasyan; M. Bartók; A. Makovec; P. Raics; Z. L. Trocsanyi; B. Ujvari; Bartók Márton (2024-) (xxx); Makovec Alajos (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Fizikai Intézet -- 749; TTK; Debreceni EgyetemThe double-differential inclusive jet cross section is measured as a function of jet transverse momentum pT and absolute rapidity |y|, using proton-proton collision data collected with the CMS experiment at the LHC, at a center-of-mass energy of √s = 2.76 TeV and corresponding to an integrated luminosity of 5.43 pb-1. Jets are reconstructed within the pT range of 74 to 592 GeV and the rapidity range |y|<3.0. The reconstructed jet spectrum is corrected for detector resolution. The measurements are compared to the theoretical prediction at next-to-leading-order QCD using different sets of parton distribution functions. This inclusive cross section measurement explores a new kinematic region and is consistent with QCD predictions.Tétel Szabadon hozzáférhető Search for monotop signatures in proton-proton collisions at s =8TeVKhachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; J. Karancsi; P. Raics; Z. L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Debreceni EgyetemResults are presented from a search for new decaying massive particles whose presence is inferred from an imbalance in transverse momentum and which are produced in association with a single top quark that decays into a bottom quark and two light quarks. The measurement is performed using 19.7 fb-1 of data from proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC. No deviations from the standard model predictions are observed and lower limits are set on the masses of new invisible bosons. In particular, scalar and vector particles, with masses below 330 and 650 GeV, respectively, are excluded at 95% confidence level, thereby substantially extending a previous limit published by the CDF Collaboration.Tétel Szabadon hozzáférhető Search for Narrow Resonances in Dijet Final States at s =8 TeV with the Novel CMS Technique of Data ScoutingKhachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; J. Karancsi; M. Bartók; A. Makovec; P. Raics; Z.L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Bartók Márton (2024-) (xxx); Makovec Alajos (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Fizikai Intézet -- 749; TTK; Debreceni EgyetemA search for narrow resonances decaying into dijet final states is performed on data from proton-proton collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 18.8 fb-1. The data were collected with the CMS detector using a novel technique called data scouting, in which the information associated with these selected events is much reduced, permitting collection of larger data samples. This technique enables CMS to record events containing jets at a rate of 1 kHz, by collecting the data from the high-level-trigger system. In this way, the sensitivity to low-mass resonances is increased significantly, allowing previously inaccessible couplings of new resonances to quarks and gluons to be probed. The resulting dijet mass distribution yields no evidence of narrow resonances. Upper limits are presented on the resonance cross sections as a function of mass, and compared with a variety of models predicting narrow resonances. The limits are translated into upper limits on the coupling of a leptophobic resonance ZB′ to quarks, improving on the results obtained by previous experiments for the mass range from 500 to 800 GeV.Tétel Szabadon hozzáférhető Search for supersymmetry in hadronic final states with missing transverse energy using the variables αT and b-quark multiplicity in pp collisions at √s = 8 TeVChatrchyan S.; Khachatryan V.; Sirunyan A.M.; J. Karancsi; P. Raics; Z.L. Trocsanyi; B. Ujvari; Karancsi János (1987-) (fizikus); Raics Péter (1944-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Debreceni EgyetemAn inclusive search for supersymmetric processes that produce final states with jets and missing transverse energy is performed in pp collisions at a centre-of-mass energy of 8 TeV. The data sample corresponds to an integrated luminosity of 11.7 fb-1 collected by the CMS experiment at the LHC. In this search, a dimensionless kinematic variable, α T, is used to discriminate between events with genuine and misreconstructed missing transverse energy. The search is based on an examination of the number of reconstructed jets per event, the scalar sum of transverse energies of these jets, and the number of these jets identified as originating from bottom quarks. No significant excess of events over the standard model expectation is found. Exclusion limits are set in the parameter space of simplified models, with a special emphasis on both compressed-spectrum scenarios and direct or gluino-induced production of third-generation squarks. For the case of gluino-mediated squark production, gluino masses up to 950-1125 GeV are excluded depending on the assumed model. For the direct pair-production of squarks, masses up to 450 GeV are excluded for a single light first- or second-generation squark, increasing to 600 GeV for bottom squarks.