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https://hdl.handle.net/2437/198859

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Megjelenítve 1 - 20 (Összesen 69)

Szabadon hozzáférhető
Azimuthal decorrelation of jets widely separated in rapidity in pp collisions at √s = 7 TeV
Khachatryan, 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); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Raics Péter (1944-) (fizikus); Makovec Alajos (1987-) (fizikus); Fizikai Intézet -- 749; TTK; Debreceni Egyetem
The decorrelation in the azimuthal angle between the most forward and the most backward jets (Mueller-Navelet jets) is measured in data collected in pp collisions with the CMS detector at the LHC at s=7 TeV. The measurement is presented in the form of distributions of azimuthal-angle differences, Δϕ, between the Mueller-Navelet jets, the average cosines of (π − Δϕ), 2(π − Δϕ), and 3(π − Δϕ), and ratios of these cosines. The jets are required to have transverse momenta, pT, in excess of 35 GeV and rapidities, |y|, of less than 4.7. The results are presented as a function of the rapidity separation, Δy, between the Mueller-Navelet jets, reaching Δy up to 9.4 for the first time. The results are compared to predictions of various Monte Carlo event generators and to analytical predictions based on the DGLAP and BFKL parton evolution schemes.
Szabadon hozzáférhető
Combined search for anomalous pseudoscalar HVV couplings in VH(H→bb‾) production and H → VV decay
Khachatryan, 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 Egyetem
A search for anomalous pseudoscalar couplings of the Higgs boson H to electroweak vector bosons V (=W or Z) in a sample of proton–proton collision events corresponding to an integrated luminosity of 18.9 fb−1 at a center-of-mass energy of 8 TeV is presented. Events consistent with the topology of associated VH production, where the Higgs boson decays to a pair of bottom quarks and the vector boson decays leptonically, are analyzed. The consistency of data with a potential pseudoscalar contribution to the HVV interaction, expressed by the effective pseudoscalar cross section fractions fa, is assessed by means of profile likelihood scans. Results are given for the VH channels alone and for a combined analysis of the VH and previously published H→VV channels. Under certain assumptions, fa ZZ>0.0034 is excluded at 95% confidence level in the combination. Scenarios in which these assumptions are relaxed are also considered.
Szabadon hozzáférhető
Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s = 7 TeV
Khachatryan, 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 Egyetem
The inclusive jet cross section for proton–proton collisions at a centre-of-mass energy of 7,TeV was measured by the CMS Collaboration at the LHC with data corresponding to an integrated luminosity of (Formula Presented.). The measurement covers a phase space up to 2, TeV in jet transverse momentum and 2.5 in absolute jet rapidity. The statistical precision of these data leads to stringent constraints on the parton distribution functions of the proton. The data provide important input for the gluon density at high fractions of the proton momentum and for the strong coupling constant at large energy scales. Using predictions from perturbative quantum chromodynamics at next-to-leading order, complemented with electroweak corrections, the constraining power of these data is investigated and the strong coupling constant at the Z boson mass (Formula Presented.), which is in agreement with the world average.
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 TeV
Khachatryan, 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 Egyetem
Stringent 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.
Szabadon hozzáférhető
Distributions of topological observables in inclusive three- and four-jet events in pp collisions at √S=7 TeV
Khachatryan, 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 Egyetem
This 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.
Szabadon hozzáférhető
Evidence for exclusive γγ → W+ W− production and constraints on anomalous quartic gauge couplings in pp collisions at √s = 7 and 8 TeV
Khachatryan, 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); Raics Péter (1944-) (fizikus); Makovec Alajos (1987-) (fizikus); Trócsányi Zoltán (1961-) (fizikus); Ujvári Balázs (1977-) (Fizikus / PhD); Fizikai Intézet -- 749; TTK; Debreceni Egyetem
A search for exclusive or quasi-exclusive γγ → W+W− production, via pp → p(*)W+W−p(*) → p(*)μ±e∓p(*) at √s = 8 TeV, is reported using data corresponding to an integrated luminosity of 19.7 fb−1. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum pT(μ±e∓) > 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 fb−1 of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 ± 0.6 (0.84 ± 0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4σ over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive γγ → W+W− production. Upper limits on the anomalous quartic gauge coupling operators a0,C W (dimension-6) and fM0,1,2,3 (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.
Szabadon hozzáférhető
Forward–backward asymmetry of Drell–Yan lepton pairs in pp collisions at √s = 8 TeV
Khachatryan, 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 Egyetem
A measurement of the forward–backward asymmetry AFB of oppositely charged lepton pairs (μμ and ee) produced via Z / γ∗ boson exchange in pp collisions at √s = 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.7 fb-1 collected with the CMS detector at the LHC. The measurement of AFB is performed for dilepton masses between 40 GeV and 2TeV and for dilepton rapidity up to 5. The AFB measurements as a function of dilepton mass and rapidity are compared with the standard model predictions.
Szabadon hozzáférhető
Inclusive and differential measurements of the tt¯ charge asymmetry in pp collisions at √s=8 TeV
Khachatryan, 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 Egyetem
The tt¯ charge asymmetry is measured in proton–proton collisions at a centre-of-mass energy of 8 TeV. The data, collected with the CMS experiment at the LHC, correspond to an integrated luminosity of 19.7 fb−1. Selected events contain an electron or a muon and four or more jets, where at least one jet is identified as originating from b-quark hadronization. The inclusive charge asymmetry is found to be 0.0010±0.0068 (stat)±0.0037 (syst). In addition, differential charge asymmetries as a function of rapidity, transverse momentum, and invariant mass of the tt¯ system are studied. For the first time at the LHC, the measurements are also performed in a reduced fiducial phase space of top quark pair production, with an integrated result of −0.0035±0.0072 (stat)±0.0031 (syst). All measurements are consistent within two standard deviations with zero asymmetry as well as with the predictions of the standard model.
Szabadon hozzáférhető
Limits on the Higgs boson lifetime and width from its decay to four charged leptons
Khachatryan, V.; Sirunyan, A. M.; Tumasyan; 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); Debreceni Egyetem
Constraints on the lifetime and width of the Higgs boson are obtained from H→ZZ→4ℓ events using data recorded by the CMS experiment during the LHC run 1 with an integrated luminosity of 5.1 and 19.7fb-1 at a center-of-mass energy of 7 and 8 TeV, respectively. The measurement of the Higgs boson lifetime is derived from its flight distance in the CMS detector with an upper bound of τH<1.9×10-13s at the 95% confidence level (C.L.), corresponding to a lower bound on the width of ΓH>3.5×10-9MeV. The measurement of the width is obtained from an off-shell production technique, generalized to include anomalous couplings of the Higgs boson to two electroweak bosons. From this measurement, a joint constraint is set on the Higgs boson width and a parameter fΛQ that expresses an anomalous coupling contribution as an on-shell cross-section fraction. The limit on the Higgs boson width is ΓH<46MeV with fΛQ unconstrained and ΓH<26MeV for fΛQ=0 at the 95% C.L. The constraint fΛQ<3.8×10-3 at the 95% C.L. is obtained for the expected standard model Higgs boson width.
Szabadon hozzáférhető
Measurement of dijet azimuthal decorrelation in pp collisions at √s=8TeV
Khachatryan, 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 Egyetem
A measurement of the decorrelation of azimuthal angles between the two jets with the largest transverse momenta is presented for seven regions of leading jet transverse momentum up to 2.2TeV. The analysis is based on the proton-proton collision data collected with the CMS experiment at a centre-of-mass energy of 8TeV corresponding to an integrated luminosity of 19.7fb-1. The dijet azimuthal decorrelation is caused by the radiation of additional jets and probes the dynamics of multijet production. The results are compared to fixed-order predictions of perturbative quantum chromodynamics (QCD), and to simulations using Monte Carlo event generators that include parton showers, hadronization, and multiparton interactions. Event generators with only two outgoing high transverse momentum partons fail to describe the measurement, even when supplemented with next-to-leading-order QCD corrections and parton showers. Much better agreement is achieved when at least three outgoing partons are complemented through either next-to-leading-order predictions or parton showers. This observation emphasizes the need to improve predictions for multijet production.
Szabadon hozzáférhető
Measurement of inclusive jet production and nuclear modifications in pPb collisions at √sNN = 5.02 TeV
Khachatryan, 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 Egyetem
Inclusive jet production in pPb collisions at a nucleon–nucleon (NN) center-of-mass energy of √sNN= 5.02TeV is studied with the CMS detector at the LHC. A data sample corresponding to an integrated luminosity of 30.1 nb- 1 is analyzed. The jet transverse momentum spectra are studied in seven pseudorapidity intervals covering the range - 2.0 < ηCM< 1.5 in the NN center-of-mass frame. The jet production yields at forward and backward pseudorapidity are compared and no significant asymmetry about ηCM= 0 is observed in the measured kinematic range. The measurements in the pPb system are compared to reference jet spectra obtained by extrapolation from previous measurements in pp collisions at √s=7TeV. In all pseudorapidity ranges, nuclear modifications in inclusive jet production are found to be small, as predicted by next-to-leading order perturbative QCD calculations that incorporate nuclear effects in the parton distribution functions.
Szabadon hozzáférhető
Measurement of J /ψ and ψ (2S) prompt double-differential cross sections in pp collisions at s =7TeV
Khachatryan, 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 Egyetem
The double-differential cross sections of promptly produced J/ψ and ψ(2S) mesons are measured in pp collisions at s=7TeV, as a function of transverse momentum pT and absolute rapidity |y|. The analysis uses J/ψ and ψ(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90fb-1, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to pT=120 and 100 GeV for the J/ψ and ψ(2S), respectively, when integrated over the interval |y|<1.2. The ratio of the ψ(2S) to J/ψ cross sections is also reported for |y|<1.2, over the range 10
Szabadon hozzáférhető
Measurement of Long-Range Near-Side Two-Particle Angular Correlations in pp Collisions at s =13 TeV
Khachatryan 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 Egyetem
Results 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 1.0
Szabadon hozzáférhető
Measurement of spin correlations in tt‾ production using the matrix element method in the muon+jets final state in pp collisions at √s=8 TeV
Khachatryan, 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 Egyetem
The consistency of the spin correlation strength in top quark pair production with the standard model (SM) prediction is tested in the muon+jets final state. The events are selected from pp collisions, collected by the CMS detector, at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.7 fb−1. The data are compared with the expectation for the spin correlation predicted by the SM and with the expectation of no correlation. Using a template fit method, the fraction of events that show SM spin correlations is measured to be 0.72±0.08(stat)−0.13 +0.15(syst), representing the most precise measurement of this quantity in the muon+jets final state to date.
Szabadon hozzáférhető
Measurement of t t ¯ production with additional jet activity, including b quark jets, in the dilepton decay channel using pp collisions at √s = 8 TeV
Khachatryan, 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 Egyetem
Jet multiplicity distributions in top quark pair (t t ¯) events are measured in pp collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC using a data set corresponding to an integrated luminosity of 19.7fb-1. The measurement is performed in the dilepton decay channels (e +e -, μ+μ-, and e ±μ∓). The absolute and normalized differential cross sections for t t ¯ production are measured as a function of the jet multiplicity in the event for different jet transverse momentum thresholds and the kinematic properties of the leading additional jets. The differential t t ¯ b and t t ¯ b b ¯ cross sections are presented for the first time as a function of the kinematic properties of the leading additional b jets. Furthermore, the fraction of events without additional jets above a threshold is measured as a function of the transverse momenta of the leading additional jets and the scalar sum of the transverse momenta of all additional jets. The data are compared and found to be consistent with predictions from several perturbative quantum chromodynamics event generators and a next-to-leading order calculation.
Szabadon hozzáférhető
Measurement of the CP-violating weak phase φs and the decay width difference δΓc using the Bs 0→J/ψφ(1020) decay channel in pp collisions at √ s=8 TeV
Khachatryan, 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 Egyetem
The CP-violating weak phase φs of the Bs0 meson and the decay width difference δΓs of the Bs0 light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of Bs0→J/ψφ(1020)→μ+μ-K+K- decays. The analysed data set corresponds to an integrated luminosity of 19.7fb-1 collected in pp collisions at a centre-of-mass energy of 8TeV. A total of 49 200 reconstructed Bs0 decays are used to extract the values of φs and δΓs by performing a time-dependent and flavour-tagged angular analysis of the μ+μ-K+K- final state. The weak phase is measured to be φs=-0.075±0.097(stat)±0.031(syst) rad, and the decay width difference is δΓs=0.095±0.013(stat)±0.007(syst) ps-1.
Szabadon hozzáférhető
Measurement of the differential cross section and charge asymmetry for inclusive pp → W±+ X production at √s = 8 TeV
Khachatryan, 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 Egyetem
The differential cross section and charge asymmetry for inclusive pp → W± + X → μ±ν + X production at √s = 8 TeV are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8fb-1 recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10-3 to 10-1.
Szabadon hozzáférhető
Measurement of the double-differential inclusive jet cross section in proton–proton collisions at $$\sqrt{s} = 13\,\text {TeV} $$ s = 13 TeV
Khachatryan, 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 Egyetem
A measurement of the double-differential inclusive jet cross section as a function of jet transverse momentum pT and absolute jet rapidity | y| is presented. The analysis is based on proton–proton collisions collected by the CMS experiment at the LHC at a centre-of-mass energy of 13TeV. The data samples correspond to integrated luminosities of 71 and 44pb-1 for | y| < 3 and 3.2 < | y| < 4.7 , respectively. Jets are reconstructed with the anti-kt clustering algorithm for two jet sizes, R, of 0.7 and 0.4, in a phase space region covering jet pT up to 2TeV and jet rapidity up to | y| = 4.7. Predictions of perturbative quantum chromodynamics at next-to-leading order precision, complemented with electroweak and nonperturbative corrections, are used to compute the absolute scale and the shape of the inclusive jet cross section. The cross section difference in R, when going to a smaller jet size of 0.4, is best described by Monte Carlo event generators with next-to-leading order predictions matched to parton showering, hadronisation, and multiparton interactions. In the phase space accessible with the new data, this measurement provides a first indication that jet physics is as well understood at s=13TeV as at smaller centre-of-mass energies.
Szabadon hozzáférhető
Measurement of the inclusive jet cross section in pp collisions at √s = 2.76 TeV
V. 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 Egyetem
The 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.
Szabadon hozzáférhető
Measurement of the inelastic cross section in proton–lead collisions at √sNN=5.02 TeV
Khachatryan, 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 Egyetem
The inelastic hadronic cross section in proton–lead collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is measured with the CMS detector at the LHC. The data sample, corresponding to an integrated luminosity of L=12.6±0.4 nb−1, has been collected with an unbiased trigger for inclusive particle production. The cross section is obtained from the measured number of proton–lead collisions with hadronic activity produced in the pseudorapidity ranges 3<η<5 and/or −5<η<−3, corrected for photon-induced contributions, experimental acceptance, and other instrumental effects. The inelastic cross section is measured to be σinel(pPb)=2061±3(stat)±34(syst)±72(lumi) mb. Various Monte Carlo generators, commonly used in heavy ion and cosmic ray physics, are found to reproduce the data within uncertainties. The value of σinel(pPb) is compatible with that expected from the proton–proton cross section at 5.02 TeV scaled up within a simple Glauber approach to account for multiple scatterings in the lead nucleus, indicating that further net nuclear corrections are small.

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