Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - Scopus: 50Observation of Electroweak Production of Wγ With Two Jets in Proton-Proton Collisions at S=13 Tev(Elsevier B.V., 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.A first observation is presented for the electroweak production of a W boson, a photon, and two jets in proton-proton collisions. The W boson decays are selected by requiring one identified electron or muon and an imbalance in transverse momentum. The two jets are required to have a high dijet mass and a large separation in pseudorapidity. The measurement is based on data collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. The observed (expected) significance for this process is 4.9 (4.6) standard deviations. After combining with previously reported CMS results at 8 TeV, the observed (expected) significance is 5.3 (4.8) standard deviations. The cross section for the electroweak Wγjj production in a restricted fiducial region is measured as 20.4±4.5fb and the total cross section for Wγ production in association with 2 jets in the same fiducial region is 108±16fb. All results are in good agreement with recent theoretical predictions. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-8 effective field theory operators. © 2020 The Author(s)Article Citation - WoS: 27Citation - Scopus: 63Evidence for Electroweak Production of Four Charged Leptons and Two Jets in Proton-Proton Collisions at S=13tev(Elsevier B.V., 2021) Sirunyan,A.M.; Karapınar, Güler; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.Evidence is presented for the electroweak (EW) production of two jets (jj) in association with two Z bosons and constraints on anomalous quartic gauge couplings are set. The analysis is based on a data sample of proton-proton collisions at s=13TeV collected with the CMS detector in 2016–2018, and corresponding to an integrated luminosity of 137fb−1. The search is performed in the fully leptonic final state ZZ→ℓℓℓ′ℓ′, where ℓ,ℓ′=e,μ. The EW production of two jets in association with two Z bosons is measured with an observed (expected) significance of 4.0 (3.5) standard deviations. The cross sections for the EW production are measured in three fiducial volumes and the result is σEW(pp→ZZjj→ℓℓℓ′ℓ′jj)=0.33−0.10 +0.11(stat)−0.03 +0.04(syst)fb in the most inclusive volume, in agreement with the standard model prediction of 0.275±0.021fb. Measurements of total cross sections for jj production in association with two Z bosons are also reported. Limits on anomalous quartic gauge couplings are derived in terms of the effective field theory operators T0, T1, T2, T8, and T9. © 2020 The Author(s)Article Citation - WoS: 34Citation - Scopus: 47Measurement of the Cp-Violating Phase Φs in the Bs 0→j/Ψϕ(1020)→μ+μ−k+k− Channel in Proton-Proton Collisions at S=13tev(Elsevier B.V., 2021) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.The CP -violating weak phase ϕs and the decay width difference ΔΓs between the light and heavy Bs 0 mass eigenstates are measured with the CMS detector at the LHC in a sample of 48500 reconstructed Bs 0→J/ψϕ(1020)→μ+μ−K+K− events. The measurement is based on a data sample corresponding to an integrated luminosity of 96.4fb−1, collected in proton-proton collisions at s=13TeV in 2017–2018. To extract the values of ϕs and ΔΓs, a time-dependent and flavor-tagged angular analysis of the μ+μ−K+K− final state is performed. The analysis employs a dedicated tagging trigger and a novel opposite-side muon flavor tagger based on machine learning techniques. The measurement yields ϕs=−11±50(stat)±10(syst)mrad and ΔΓs=0.114±0.014(stat)±0.007(syst)ps−1, in agreement with the standard model predictions. When combined with the previous CMS measurement at s=8TeV, the following values are obtained: ϕs=−21±44(stat)±10(syst)mrad, ΔΓs=0.1032±0.0095(stat)±0.0048(syst)ps−1, a significant improvement over the 8 TeV result. © 2021 The Author(s)Article Citation - WoS: 74Citation - Scopus: 87Search for Disappearing Tracks in Proton-Proton Collisions at S=13tev(Elsevier B.V., 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.A search is presented for long-lived charged particles that decay within the volume of the silicon tracker of the CMS experiment. Such particles can produce events with an isolated track that is missing hits in the outermost layers of the silicon tracker, and is also associated with little energy deposited in the calorimeters and no hits in the muon detectors. The search for events with this “disappearing track” signature is performed in a sample of proton-proton collisions recorded by the CMS experiment at the LHC with a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 101fb−1 recorded in 2017 and 2018. The observation of 48 events is consistent with the estimated background of 47.8−2.3 +2.7(stat)±8.1(syst) events. Upper limits are set on chargino production in the context of an anomaly-mediated supersymmetry breaking model for purely wino and higgsino neutralino scenarios. At 95% confidence level, the first constraint is placed on chargino masses in the higgsino case, excluding below 750 (175) GeV for a lifetime of 3 (0.05) ns. In the wino case, the results of this search are combined with a previous CMS search to produce a result representing the complete LHC data set recorded in 2015–2018, the most stringent constraints to date. At 95% confidence level, chargino masses in the wino case are excluded below 884 (474) GeV for a lifetime of 3 (0.2) ns. © 2020 The Author(s)Article Citation - WoS: 20Citation - Scopus: 28Measurement of Ckm Matrix Elements in Single Top Quark T-Channel Production in Proton-Proton Collisions at S=13 Tev(Elsevier B.V., 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Sobol, A.The first direct, model-independent measurement is presented of the modulus of the Cabibbo–Kobayashi–Maskawa (CKM) matrix elements |η|Vtb, |η|Vtd, and |η|Vts, in final states enriched in single top quark t-channel events. The analysis uses proton-proton collision data from the LHC, collected during 2016 by the CMS experiment, at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. Processes directly sensitive to these matrix elements are considered at both the production and decay vertices of the top quark. In the standard model hypothesis of CKM unitarity, a lower limit of |η|Vtb>0.970 is measured at the 95% confidence level. Several theories beyond the standard model are considered, and by releasing all constraints among the involved parameters, the values |η|Vtb=0.988±0.024, and |η|Vtd 2+|η|Vts 2=0.06±0.06, where the uncertainties include both statistical and systematic components, are measured. © 2020 The AuthorArticle Citation - WoS: 112Citation - Scopus: 88Measurements of Production Cross Sections of Wz and Same-Sign Ww Boson Pairs in Association With Two Jets in Proton-Proton Collisions at S=13tev(Elsevier B.V., 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.Measurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at s=13TeV at the LHC are reported. The data sample corresponds to an integrated luminosity of 137fb−1, collected with the CMS detector during 2016–2018. The measurements are performed in the leptonic decay modes [Formula presented] and [Formula presented], where ℓ,ℓ′=e, [Formula presented]. Differential fiducial cross sections as functions of the invariant masses of the jet and charged lepton pairs, as well as of the leading-lepton transverse momentum, are measured for W±W± production and are consistent with the standard model predictions. The dependence of differential cross sections on the invariant mass of the jet pair is also measured for WZ production. An observation of electroweak production of WZ boson pairs is reported with an observed (expected) significance of 6.8 (5.3) standard deviations. Constraints are obtained on the structure of quartic vector boson interactions in the framework of effective field theory. © 2020 The AuthorArticle Citation - WoS: 56Citation - Scopus: 60Search for Lepton Flavour Violating Decays of the Higgs Boson To Eτ and Eμ in Proton–proton Collisions at S=8 Tev(Elsevier B.V., 2016) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Trevisani, N.A direct search for lepton flavour violating decays of the Higgs boson (H) in the H→eτ and H→eμ channels is described. The data sample used in the search was collected in proton–proton collisions at s=8 TeV with the CMS detector at the LHC and corresponds to an integrated luminosity of 19.7 fb−1. No evidence is found for lepton flavour violating decays in either final state. Upper limits on the branching fractions, B(H→eτ)<0.69% and B(H→eμ)<0.035%, are set at the 95% confidence level. The constraint set on B(H→eτ) is an order of magnitude more stringent than the existing indirect limits. The limits are used to constrain the corresponding flavour violating Yukawa couplings, absent in the standard model. © 2016 The Author(s)Article Citation - WoS: 8Citation - Scopus: 10ϒ(ns) Polarizations Versus Particle Multiplicity in Pp Collisions at S=7 Tev(Elsevier B.V., 2016) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Flix, J.The polarizations of the ϒ(1S), ϒ(2S), and ϒ(3S) mesons are measured as a function of the charged particle multiplicity in proton–proton collisions at s=7 TeV. The measurements are performed with a dimuon data sample collected in 2011 by the CMS experiment, corresponding to an integrated luminosity of 4.9 fb−1. The results are extracted from the dimuon decay angular distributions, in two ranges of ϒ(nS) transverse momentum (10–15 and 15–35 GeV), and in the rapidity interval |y|>1.2. The results do not show significant changes from low- to high-multiplicity pp collisions, although large uncertainties preclude definite statements in the ϒ(2S) and ϒ(3S) cases. © 2016 The Author(s)Article Citation - WoS: 24Citation - Scopus: 22Search for Top Squark Pair Production in Compressed-Mass Scenarios in Proton-Proton Collisions at S=8 Tev Using the Αt Variable(Elsevier B.V., 2017) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Cabrillo, I.J.An inclusive search is performed for supersymmetry in final states containing jets and an apparent imbalance in transverse momentum, p→T miss, due to the production of unobserved weakly interacting particles in pp collisions at a centre-of-mass energy of 8 TeV. The data, recorded with the CMS detector at the CERN LHC, correspond to an integrated luminosity of 18.5 fb−1. The dimensionless kinematic variable αT is used to discriminate between events with genuine p→T miss associated with unobserved particles and spurious values of p→T miss arising from jet energy mismeasurements. No excess of event yields above the expected standard model backgrounds is observed. The results are interpreted in terms of constraints on the parameter space of several simplified models of supersymmetry that assume the pair production of top squarks. The search provides sensitivity to a broad range of top squark (t˜) decay modes, including the two-body decay t˜→cχ˜1°, where c is a charm quark and χ˜1° is the lightest neutralino, as well as the four-body decay t˜→bff¯′χ˜1°, where b is a bottom quark and f and f¯′ are fermions produced in the decay of an intermediate off-shell W boson. These modes dominate in scenarios in which the top squark and lightest neutralino are nearly degenerate in mass. For these modes, top squarks with masses as large as 260 and 225 GeV are excluded, respectively, for the two- and four-body decays. © 2017 The AuthorArticle Citation - WoS: 338Citation - Scopus: 288Evidence for Collectivity in Pp Collisions at the Lhc(Elsevier B.V., 2017) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Dubinin, M.Measurements of two- and multi-particle angular correlations in pp collisions at s=5,7, and 13TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0pb−1 (5 TeV), 6.2pb−1 (7 TeV), and 0.7pb−1 (13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of KS 0 and Λ/Λ‾ particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v2 values of charged hadrons (mostly pions), KS 0, and Λ/Λ‾, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT≈2GeV/c. For 13 TeV data, the v2 signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions. © 2016 The Author