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Article Citation - WoS: 4Citation - Scopus: 8Search for the Rare Decay of the W Boson Into a Pion and a Photon 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.A search is performed for the rare decay W±→π±γ in proton-proton collisions at s=13TeV. Data corresponding to an integrated luminosity of 137fb−1 were collected during 2016 to 2018 with the CMS detector. This analysis exploits a novel search strategy based on W boson production in top quark pair events. An inclusive search for the W±→π±γ decay is not optimal at the LHC because of the high trigger thresholds. Instead, a trigger selection is exploited in which the W boson originating from one of the top quarks is used to tag the event in a leptonic decay. The W boson emerging from the other top quark is used to search for the W±→π±γ signature. Such decays are characterized by an isolated track pointing to a large energy deposit, and by an isolated photon of large transverse momentum. The presence of b quark jets reduces the background from the hadronization of light-flavor quarks and gluons. The W±→π±γ decay is not observed. An upper exclusion limit is set to this branching fraction, corresponding to 1.50×10−5 at 95% confidence level, whereas the expected upper exclusion limit is 0.85−0.29 +0.52×10−5. © 2021 The Author(s)Article Citation - WoS: 26Citation - Scopus: 27Measurement of the Azimuthal Anisotropy of [Formula Presented] and [Formula Presented] Mesons in PbPb Collisions at S NN =5.02 TeV(Elsevier B.V., 2021) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; De Jesus Damiao, D.The second-order Fourier coefficients (v<inf>2</inf>) characterizing the azimuthal distributions of [Formula presented] and [Formula presented] mesons produced in PbPb collisions at s<inf> <inf>NN</inf> </inf>=5.02TeV are studied. The [Formula presented] mesons are reconstructed in their dimuon decay channel, as measured by the CMS detector. The collected data set corresponds to an integrated luminosity of 1.7nb−1. The scalar product method is used to extract the v<inf>2</inf> coefficients of the azimuthal distributions. Results are reported for the rapidity range |y|<2.4, in the transverse momentum interval 0<p<inf>T</inf><50GeV/c, and in three centrality ranges of 10–30%, 30–50% and 50–90%. In contrast to the J/ψ mesons, the measured v<inf>2</inf> values for the [Formula presented] mesons are found to be consistent with zero. © 2021 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: 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: 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: 26Citation - Scopus: 27Measurement of the Zγ→νν‾γ production cross section in pp collisions at s=8 TeV and limits on anomalous ZZγ and Zγγ trilinear gauge boson couplings(Elsevier B.V., 2016) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Josa, M.I.An inclusive measurement of the Zγ→νν‾γ production cross section in pp collisions at s=8TeV is presented, using data corresponding to an integrated luminosity of 19.6 fb−1 collected with the CMS detector at the LHC. This measurement is based on the observation of events with large missing energy and with a single photon with transverse momentum above 145GeV and absolute pseudorapidity in the range |η|<1.44. The measured Zγ→νν‾γ production cross section, 52.7±2.1 (stat)±6.4 (syst)±1.4 (lumi) fb, agrees well with the standard model prediction of 50.0−2.2 +2.4 fb. A study of the photon transverse momentum spectrum yields the most stringent limits to date on the anomalous ZZγ and Zγγ trilinear gauge boson couplings. © 2016 The Author(s)Article Citation - WoS: 90Citation - Scopus: 98Search for High-Mass Diphoton Resonances in Proton–proton Collisions at 13 Tev and Combination With 8 Tev Search(Elsevier B.V., 2017) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Elumakhov, D.A search for the resonant production of high-mass photon pairs is presented. The search focuses on spin-0 and spin-2 resonances with masses between 0.5 and 4.5 TeV, and with widths, relative to the mass, between 1.4×10−4 and 5.6×10−2. The data sample corresponds to an integrated luminosity of 12.9 fb−1 of proton–proton collisions collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV. No significant excess is observed relative to the standard model expectation. The results of the search are combined statistically with those previously obtained in 2012 and 2015 at s=8 and 13 TeV, respectively, corresponding to integrated luminosities of 19.7 and 3.3 fb−1, to derive exclusion limits on scalar resonances produced through gluon–gluon fusion, and on Randall–Sundrum gravitons. The lower mass limits for Randall–Sundrum gravitons range from 1.95 to 4.45 TeV for coupling parameters between 0.01 and 0.2. These are the most stringent limits on Randall–Sundrum graviton production to date. © 2017 The AuthorArticle 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: 44Citation - Scopus: 53Measurement of the Cross Section for Electroweak Production of Zγ in Association With Two Jets and Constraints on Anomalous Quartic Gauge Couplings in Proton–proton Collisions at S=8 Tev(Elsevier B.V., 2017) Khachatryan, V.; Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Piedra Gomez, J.A measurement is presented of the cross section for the electroweak production of a Z boson and a photon in association with two jets in proton–proton collisions at s=8 TeV. The Z bosons are identified through their decays to electron or muon pairs. The measurement is based on data collected with the CMS detector corresponding to an integrated luminosity of 19.7 fb−1. The electroweak contribution has a significance of 3.0 standard deviations, and the measured fiducial cross section is 1.86−0.75 +0.90(stat)−0.26 +0.34(syst)±0.05(lumi) fb, while the summed electroweak and quantum chromodynamic total cross section in the same region is observed to be 5.94−1.35 +1.53(stat)−0.37 +0.43(syst)±0.13(lumi) fb. Both measurements are consistent with the leading-order standard model predictions. Limits on anomalous quartic gauge couplings are set based on the Zγ mass distribution. © 2017 The AuthorArticle Citation - WoS: 36Citation - Scopus: 38Search for Single Production of Vector-Like Quarks Decaying Into a B Quark and a W Boson in Proton–proton Collisions at S=13tev(Elsevier B.V., 2017) Belknap, D.A.; Buchanan, J.; Caillol, C.; Dasu, S.; Dodd, L.; Duric, S.; Redondo, I.A search is presented for a heavy vector-like quark, decaying into a b quark and a W boson, which is produced singly in association with a light flavor quark and a b quark. The analysis is performed using a data sample of proton–proton collisions at a center-of-mass energy of s=13TeV collected at the LHC in 2015. The data set used in the analysis corresponds to an integrated luminosity of 2.3fb−1. The search is carried out using events containing one electron or muon, at least one b-tagged jet with large transverse momentum, at least one jet in the forward region of the detector, and missing transverse momentum. No excess over the standard model prediction is observed. Upper limits are placed on the production cross section of heavy exotic quarks: a T quark with a charge of 2/3, and a Y quark with a charge of −4/3. For Y quarks with coupling of 0.5 and B(Y→bW)=100%, the observed (expected) lower mass limits are 1.40 (1.0)TeV. This is the most stringent limit to date on the single production of the Y vector-like quark. © 2017 The Author(s)