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Article Citation - WoS: 86Citation - Scopus: 8Measurement of Single-Diffractive Dijet Production in Proton–proton Collisions at √s=8te With the Cms and Totem Experiments(Springer Nature, 2020) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Josa, M.I.Measurements are presented of the single-diffractive dijet cross section and the diffractive cross section as a function of the proton fractional momentum loss ξ and the four-momentum transfer squared t. Both processes pp→pX and pp→Xp, i.e. with the proton scattering to either side of the interaction point, are measured, where X includes at least two jets; the results of the two processes are averaged. The analyses are based on data collected simultaneously with the CMS and TOTEM detectors at the LHC in proton–proton collisions at s=8Te during a dedicated run with β∗=90m at low instantaneous luminosity and correspond to an integrated luminosity of 37.5nb-1. The single-diffractive dijet cross section σjjpX, in the kinematic region ξ< 0.1 , 0.03<|t|<1Ge2, with at least two jets with transverse momentum pT>40Ge, and pseudorapidity | η| < 4.4 , is 21.7±0.9(stat)-3.3+3.0(syst)±0.9(lumi)nb. The ratio of the single-diffractive to inclusive dijet yields, normalised per unit of ξ, is presented as a function of x, the longitudinal momentum fraction of the proton carried by the struck parton. The ratio in the kinematic region defined above, for x values in the range - 2.9 ≤ log 10x≤ - 1.6 , is R=(σjjpX/Δξ)/σjj=0.025±0.001(stat)±0.003(syst), where σjjpX and σjj are the single-diffractive and inclusive dijet cross sections, respectively. The results are compared with predictions from models of diffractive and nondiffractive interactions. Monte Carlo predictions based on the HERA diffractive parton distribution functions agree well with the data when corrected for the effect of soft rescattering between the spectator partons. © 2020, CERN for the benefit of the CMS and TOTEM collaborations.Article Citation - WoS: 17Citation - Scopus: 19Measurement of Electroweak Production of a W Boson in Association With Two Jets in Proton–proton Collisions at √s=13te(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Gonzalez Lopez, O.A measurement is presented of electroweak (EW) production of a W boson in association with two jets in proton–proton collisions at s=13Te. The data sample was recorded by the CMS Collaboration at the LHC and corresponds to an integrated luminosity of 35.9fb-1. The measurement is performed for the ℓνjj final state (with ℓν indicating a lepton–neutrino pair, and j representing the quarks produced in the hard interaction) in a kinematic region defined by invariant mass mjj>120Ge and transverse momenta pTj>25Ge. The cross section of the process is measured in the electron and muon channels yielding σEW(Wjj)=6.23±0.12(stat)±0.61(syst)pb per channel, in agreement with leading-order standard model predictions. The additional hadronic activity of events in a signal-enriched region is studied, and the measurements are compared with predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. Limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.3<cWWW/Λ2<2.5Te-2, -8.8<cW/Λ2<16Te-2, and -45<cB/Λ2<46Te-2. These results are combined with the CMS EW Zjj analysis, yielding the constraint on the cW W W coupling: -1.8<cWWW/Λ2<2.0Te-2. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 77Citation - Scopus: 90Measurement of T T ¯ Normalised Multi-Differential Cross Sections in Pp Collisions at √s=13tev , and Simultaneous Determination of the Strong Coupling Strength, Top Quark Pole Mass, and Parton Distribution Functions(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Goy Lopez, S.Normalised multi-differential cross sections for top quark pair (t t ¯) production are measured in proton-proton collisions at a centre-of-mass energy of 13TeV using events containing two oppositely charged leptons. The analysed data were recorded with the CMS detector in 2016 and correspond to an integrated luminosity of 35.9fb-1. The double-differential t t ¯ cross section is measured as a function of the kinematic properties of the top quark and of the t t ¯ system at parton level in the full phase space. A triple-differential measurement is performed as a function of the invariant mass and rapidity of the t t ¯ system and the multiplicity of additional jets at particle level. The data are compared to predictions of Monte Carlo event generators that complement next-to-leading-order (NLO) quantum chromodynamics (QCD) calculations with parton showers. Together with a fixed-order NLO QCD calculation, the triple-differential measurement is used to extract values of the strong coupling strength αS and the top quark pole mass (mtpole) using several sets of parton distribution functions (PDFs). The measurement of mtpole exploits the sensitivity of the t t ¯ invariant mass distribution to mtpole near the production threshold. Furthermore, a simultaneous fit of the PDFs, αS, and mtpole is performed at NLO, demonstrating that the new data have significant impact on the gluon PDF, and at the same time allow an accurate determination of αS and mtpole. The values αS(mZ)=0.1135-0.0017+0.0021 and mtpole=170.5±0.8GeV are extracted, which account for experimental and theoretical uncertainties, the latter being estimated from NLO scale variations. Possible effects from Coulomb and soft-gluon resummation near the t t ¯ production threshold are neglected in these parameter extractions. A rough estimate of these effects indicates an expected correction of mtpole of the order of +1GeV, which can be regarded as additional theoretical uncertainty in the current mtpole extraction. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 6Citation - Scopus: 10Study of Central Exclusive [inlineequation Not Available: See Fulltext.] Production in Proton-Proton Collisions at √s=5.02 and 13tev(Springer Nature, 2020) Sirunyan, A.M.; Karapınar, Güler; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Kachanov, V.Central exclusive and semiexclusive production of [InlineEquation not available: see fulltext.] pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, whereas the absence of other particles is ensured by calorimeter information. The total and differential cross sections of exclusive and semiexclusive central [InlineEquation not available: see fulltext.] production are measured as functions of invariant mass, transverse momentum, and rapidity of the [InlineEquation not available: see fulltext.] system in the fiducial region defined as transverse momentum [InlineEquation not available: see fulltext.] and pseudorapidity [InlineEquation not available: see fulltext.]. The production cross sections for the four resonant channels [InlineMediaObject not available: see fulltext.], [InlineEquation not available: see fulltext.], [InlineMediaObject not available: see fulltext.], and [InlineMediaObject not available: see fulltext.]are extracted using a simple model. These results represent the first measurement of this process at the LHC collision energies of 5.02 and 13TeV. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 42Citation - Scopus: 46Search for Physics Beyond the Standard Model in Events With Jets and Two Same-Sign or at Least Three Charged Leptons in Proton-Proton Collisions at √s=13tev(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Dragicevic, M.; Milenovic, P.A data sample of events from proton-proton collisions with at least two jets, and two isolated same-sign or three or more charged leptons, is studied in a search for signatures of new physics phenomena. The data correspond to an integrated luminosity of 137fb-1 at a center-of-mass energy of 13TeV, collected in 2016–2018 by the CMS experiment at the LHC. The search is performed using a total of 168 signal regions defined using several kinematic variables. The properties of the events are found to be consistent with the expectations from standard model processes. Exclusion limits at 95% confidence level are set on cross sections for the pair production of gluinos or squarks for various decay scenarios in the context of supersymmetric models conserving or violating R parity. The observed lower mass limits are as large as 2.1TeV for gluinos and 0.9TeV for top and bottom squarks. To facilitate reinterpretations, model-independent limits are provided in a set of simplified signal regions. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 80Citation - Scopus: 84Searches for Physics Beyond the Standard Model With the Mt 2 Variable in Hadronic Final States With and Without Disappearing Tracks in Proton–proton Collisions at √s=13te(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Uzunian, A.Two related searches for phenomena beyond the standard model (BSM) are performed using events with hadronic jets and significant transverse momentum imbalance. The results are based on a sample of proton–proton collisions at a center-of-mass energy of 13Te, collected by the CMS experiment at the LHC in 2016–2018 and corresponding to an integrated luminosity of 137fb-1. The first search is inclusive, based on signal regions defined by the hadronic energy in the event, the jet multiplicity, the number of jets identified as originating from bottom quarks, and the value of the kinematic variable MT 2 for events with at least two jets. For events with exactly one jet, the transverse momentum of the jet is used instead. The second search looks in addition for disappearing tracks produced by BSM long-lived charged particles that decay within the volume of the tracking detector. No excess event yield is observed above the predicted standard model background. This is used to constrain a range of BSM models that predict the following: the pair production of gluinos and squarks in the context of supersymmetry models conserving R-parity, with or without intermediate long-lived charginos produced in the decay chain; the resonant production of a colored scalar state decaying to a massive Dirac fermion and a quark; or the pair production of scalar and vector leptoquarks each decaying to a neutrino and a top, bottom, or light-flavor quark. In most of the cases, the results obtained are the most stringent constraints to date. © 2019, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 304Citation - Scopus: 356Extraction and Validation of a New Set of Cms Pythia8 Tunes From Underlying-Event Measurements(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Fernandez Bedoya, C.New sets of CMS underlying-event parameters (“tunes”) are presented for the pythia8 event generator. These tunes use the NNPDF3.1 parton distribution functions (PDFs) at leading (LO), next-to-leading (NLO), or next-to-next-to-leading (NNLO) orders in perturbative quantum chromodynamics, and the strong coupling evolution at LO or NLO. Measurements of charged-particle multiplicity and transverse momentum densities at various hadron collision energies are fit simultaneously to determine the parameters of the tunes. Comparisons of the predictions of the new tunes are provided for observables sensitive to the event shapes at LEP, global underlying event, soft multiparton interactions, and double-parton scattering contributions. In addition, comparisons are made for observables measured in various specific processes, such as multijet, Drell–Yan, and top quark-antiquark pair production including jet substructure observables. The simulation of the underlying event provided by the new tunes is interfaced to a higher-order matrix-element calculation. For the first time, predictions from pythia8 obtained with tunes based on NLO or NNLO PDFs are shown to reliably describe minimum-bias and underlying-event data with a similar level of agreement to predictions from tunes using LO PDF sets. © 2019, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 22Citation - Scopus: 30Evidence for Ww Production From Double-Parton Interactions in Proton–proton Collisions at √s=13tev(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Snigirev, A.A search for WW production from double-parton scattering processes using same-charge electron-muon and dimuon events is reported, based on proton-proton collision data collected at a center-of-mass energy of 13TeV. The analyzed data set corresponds to an integrated luminosity of 77.4fb-1, collected using the CMS detector at the LHC in 2016 and 2017. Multivariate classifiers are used to discriminate between the signal and the dominant background processes. A maximum likelihood fit is performed to extract the signal cross section. This leads to the first evidence for WW production via double-parton scattering, with a significance of 3.9 standard deviations. The measured inclusive cross section is 1.41±0.28(stat)±0.28(syst)pb. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 21Citation - Scopus: 33Search for Direct Pair Production of Supersymmetric Partners To the Τ Lepton in Proton–proton Collisions at √s=13tev(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Bitioukov, S.A search is presented for τ slepton pairs produced in proton–proton collisions at a center-of-mass energy of 13TeV. The search is carried out in events containing two τ leptons in the final state, on the assumption that each τ slepton decays primarily to a τ lepton and a neutralino. Events are considered in which each τ lepton decays to one or more hadrons and a neutrino, or in which one of the τ leptons decays instead to an electron or a muon and two neutrinos. The data, collected with the CMS detector in 2016 and 2017, correspond to an integrated luminosity of 77.2fb-1. The observed data are consistent with the standard model background expectation. The results are used to set 95% confidence level upper limits on the cross section for τ slepton pair production in various models for τ slepton masses between 90 and 200GeV and neutralino masses of 1, 10, and 20GeV. In the case of purely left-handed τ slepton production and decay to a τ lepton and a neutralino with a mass of 1GeV, the strongest limit is obtained for a τ slepton mass of 125GeV at a factor of 1.14 larger than the theoretical cross section. © 2020, CERN for the benefit of the CMS collaboration.Article Citation - WoS: 102Citation - Scopus: 122Search for Production of Four Top Quarks in Final States With Same-Sign or Multiple Leptons in Proton–proton Collisions at √s=13tev(Springer Nature, 2020) Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bergauer, T.; Brandstetter, J.; Slabospitskii, S.The standard model (SM) production of four top quarks (t t ¯ t t ¯) in proton–proton collisions is studied by the CMS Collaboration. The data sample, collected during the 2016–2018 data taking of the LHC, corresponds to an integrated luminosity of 137fb-1 at a center-of-mass energy of 13TeV. The events are required to contain two same-sign charged leptons (electrons or muons) or at least three leptons, and jets. The observed and expected significances for the t t ¯ t t ¯ signal are respectively 2.6 and 2.7 standard deviations, and the t t ¯ t t ¯ cross section is measured to be 12.6-5.2+5.8fb. The results are used to constrain the Yukawa coupling of the top quark to the Higgs boson, yt, yielding a limit of |yt/ytSM|<1.7 at 95 % confidence level, where ytSM is the SM value of yt. They are also used to constrain the oblique parameter of the Higgs boson in an effective field theory framework, H^ < 0.12. Limits are set on the production of a heavy scalar or pseudoscalar boson in Type-II two-Higgs-doublet and simplified dark matter models, with exclusion limits reaching 350–470GeV and 350–550GeV for scalar and pseudoscalar bosons, respectively. Upper bounds are also set on couplings of the top quark to new light particles. © 2020, CERN for the benefit of the CMS collaboration.