Browsing by Subject "EXTENSION"

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  • The CMS collaboration; Tumasyan, A.; Adam, W.; Eerola, P.; Forthomme, Laurent; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Bharthuar, Shudhashil; Brücken, Erik; Garcia, F.; Havukainen, J.; Heikkilä, Jaana; Kim, Minsuk; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Lotti, Mikko; Luukka, P.; Martikainen, Laura; Myllymäki, Mikael Erkki Johannes; Ott, Jennifer; Pekkanen, Juska; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, Jussi; Petrow, H.; Tuuva, T. (2021)
    A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    The results of a previous search by the CMS Collaboration for squarks and gluinos are reinterpreted to constrain models of leptoquark (LQ) production. The search considers jets in association with a transverse momentum imbalance, using the M-T2 variable. The analysis uses proton-proton collision data at root s = 13 TeV, recorded with the CMS detector at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb(-1). Leptoquark pair production is considered with LQ decays to a neutrino and a top, bottom, or light quark. This reinterpretation considers higher mass values than the original CMS search to constrain both scalar and vector LQs. Limits on the cross section for LQ pair production are derived at the 95% confidence level depending on the LQ decay mode. A vector LQ decaying with a 50% branching fraction to t nu, and 50% to b tau, has been proposed as part of an explanation of anomalous flavor physics results. In such a model, using only the decays to t nu, LQ masses below 1530 GeV are excluded assuming the Yang-Mills case with coupling kappa = 1, or 1115 GeV in the minimal coupling case kappa = 0, placing the most stringent constraint to date from pair production of vector LQs.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    An inclusive search for supersymmetry (SUSY) using the razor variables is performed using a data sample of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb(-1), collected with the CMS experiment in 2016 at a center-of-mass energy of =13 TeV. The search looks for an excess of events with large transverse energy, large jet multiplicity, and large missing transverse momentum. The razor kinematic variables are sensitive to large mass differences between the parent particle and the invisible particles of a decay chain and help to identify the presence of SUSY particles. The search covers final states with zero or one charged lepton and features event categories divided according to the presence of a high transverse momentum hadronically decaying W boson or top quark, the number of jets, the number of b-tagged jets, and the values of the razor kinematic variables, in order to separate signal from background for a broad range of SUSY signatures. The addition of the boosted W boson and top quark categories within the analysis further increases the sensitivity of the search, particularly to signal models with large mass splitting between the produced gluino or squark and the lightest SUSY particle. The analysis is interpreted using simplified models of R-parity conserving SUSY, focusing on gluino pair production and top squark pair production. Limits on the gluino mass extend to 2.0 TeV, while limits on top squark mass reach 1.14 TeV.
  • Souza, Paulo C. T.; Alessandri, Riccardo; Barnoud, Jonathan; Thallmair, Sebastian; Faustino, Ignacio; Grunewald, Fabian; Patmanidis, Ilias; Abdizadeh, Haleh; Bruininks, Bart M. H.; Wassenaar, Tsjerk A.; Kroon, Peter C.; Melcr, Josef; Nieto, Vincent; Corradi, Valentina; Khan, Hanif M.; Domanski, Jan; Javanainen, Matti; Martinez-Seara, Hector; Reuter, Nathalie; Best, Robert B.; Vattulainen, Ilpo; Monticelli, Luca; Periole, Xavier; Tieleman, D. Peter; de Vries, Alex H.; Marrink, Siewert J. (2021)
    The coarse-grained Martini force field is widely used in biomolecular simulations. Here we present the refined model, Martini 3 (http://cgmartini.nl), with an improved interaction balance, new bead types and expanded ability to include specific interactions representing, for example, hydrogen bonding and electronic polarizability. The updated model allows more accurate predictions of molecular packing and interactions in general, which is exemplified with a vast and diverse set of applications, ranging from oil/water partitioning and miscibility data to complex molecular systems, involving protein-protein and protein-lipid interactions and material science applications as ionic liquids and aedamers.
  • Harjulehto, Petteri; Hurri-Syrjänen, Ritva (2018)
    In a smooth domain a function can be estimated pointwise by the classical Riesz potential of its gradient. Combining this estimate with the boundedness of the classical Riesz potential yields the optimal Sobolev-Poincar, inequality. We show that this method gives a Sobolev-Poincar, inequality also for irregular domains whenever we use the modified Riesz potential which arise naturally from the geometry of the domain. The exponent of the Sobolev-Poincar, inequality depends on the domain. The Sobolev-Poincar, inequality given by this approach is not sharp for irregular domains, although the embedding for the modified Riesz potential is optimal. In order to obtain the results we prove a new pointwise estimate for the Hardy-Littlewood maximal operator.
  • The CMS collaboration; Tumasyan, A.; Adam, W.; Eerola, P.; Forthomme, Laurent; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Bharthuar, Shudhashil; Brücken, Erik; Garcia, F.; Havukainen, J.; Heikkilä, Jaana; Kim, Minsuk; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Lotti, Mikko; Luukka, P.; Martikainen, Laura; Myllymäki, Mikael Erkki Johannes; Ott, Jennifer; Pekkanen, Juska; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, Jussi; Petrow, H.; Tuuva, T. (2021)
    A search for a heavy Higgs boson H decaying into the observed Higgs boson h with a mass of 125 GeV and another Higgs boson h(S) is presented. The h and h(S) bosons are required to decay into a pair of tau leptons and a pair of b quarks, respectively. The search uses a sample of proton-proton collisions collected with the CMS detector at a center-of-mass energy of 13TeV, corresponding to an integrated luminosity of 137 fb(-1). Mass ranges of 240-3000 GeV for m(H) and 60-2800 GeV for m(hS) are explored in the search. No signal has been observed. Model independent 95% confidence level upper limits on the product of the production cross section and the branching fractions of the signal process are set with a sensitivity ranging from 125 fb (for m(H) = 240 GeV) to 2.7 fb (for m(H) = 1000 GeV). These limits are compared to maximally allowed products of the production cross section and the branching fractions of the signal process in the next-to-minimal supersymmetric extension of the standard model.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    The results of a search for a standard model-like Higgs boson in the mass range between 70 and 110 GeV decaying into two photons are presented. The analysis uses the data set collected with the CMS experiment in proton-proton collisions during the 2012 and 2016 LHC running periods. The data sample corresponds to an integrated luminosity of 19.7 (35.9) fb(-1) at root s = 8 (13) TeV. The expected and observed 95% confidence level upper limits on the product of the cross section and branching fraction into two photons are presented. The observed upper limit for the 2012 (2016) data set ranges from 129 (161) fb to 31 (26) fb. The statistical combination of the results from the analyses of the two data sets in the common mass range between 80 and 110 GeV yields an upper limit on the product of the cross section and branching fraction, normalized to that for a standard model-like Higgs boson, ranging from 0.7 to 0.2, with two notable exceptions: one in the region around the Z boson peak, where the limit rises to 1.1, which may be due to the presence of Drell-Yan dielectron production where electrons could be misidentified as isolated photons, and a second due to an observed excess with respect to the standard model prediction, which is maximal for a mass hypothesis of 95.3 GeV with a local (global) significance of 2.8 (1.3) standard deviations. (C) 2019 The Author(s). Published by Elsevier B.V.
  • The CMS collaboration; Eerola, P.; Forthomme, L.; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Garcia, F.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Kinnunen, R.; Lampen, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Linden, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Pekkanen, J.; Tuuva, T.; Karimäki, V.; Sirunyan, A. M.; Tumasyan, A. (2020)
    A search is presented for t slepton pairs produced in proton-proton collisions at a center-of-mass energy of 13 TeV. The search is carried out in events containing two t leptons in the final state, on the assumption that each t slepton decays primarily to a t lepton and a neutralino. Events are considered in which each t lepton decays to one or more hadrons and a neutrino, or in which one of the t 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 77.2 fb-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 t slepton pair production in various models for t slepton masses between 90 and 200 GeV and neutralino masses of 1, 10, and 20 GeV. In the case of purely left-handed t slepton production and decay to a t lepton and a neutralino with a mass of 1GeV, the strongest limit is obtained for a t slepton mass of 125 GeV at a factor of 1.14 larger than the theoretical cross section.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    A search for gauge-mediated supersymmetry (SUSY) in final states with photons and large missing transverse momentum is presented. The data sample of pp collisions at root s= 13 TeV was collected with the CMS detector at the CERN LHC and corresponds to an integrated luminosity of 35.9 fb(-1). Data are compared with models in which the lightest neutralino has bino- or wino-like components, resulting in decays to photons and gravitinos, where the gravitinos escape detection. The event selection is optimized for both electroweak (EWK) and strong production SUSY scenarios. The observed data are consistent with standard model predictions, and limits are set in the context of a general gauge mediation model in which gaugino masses up to 980 GeV are excluded at 95% confidence level. Gaugino masses below 780 and 950 GeV are excluded in two simplified models with EWK production of mass-degenerate charginos and neutralinos. Stringent limits are set on simplified models based on gluino and squark pair production, excluding gluino (squark) masses up to 2100 (1750)GeV depending on the assumptions made for the decay modes and intermediate particle masses. This analysis sets the highest mass limits to date in the studied EWK models, and in the considered strong production models when the mass difference between the gauginos and the squarks or gluinos is small. (C) 2018 The Author. Published by Elsevier B.V.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    A search for new particles has been conducted using events with two high transverse momentum leptons that decay hadronically and at least two energetic jets. The analysis is performed using data from proton-proton collisions at 13 TeV, collected by the CMS experiment at the LHC in 2016 and corresponding to an integrated luminosity of 35.9 fb(-1). The observed data are consistent with standard model expectations. The results are interpreted in the context of two physics models. The first model involves right-handed charged bosons, W-R, that decay to heavy right-handed Majorana neutrinos, N ( = e, , ), arising in a left-right symmetric extension of the standard model. The model considers that N-e and N are too heavy to be detected at the LHC. Assuming that the N mass is half of the W-R mass, masses of the W-R boson below 3.50 TeV are excluded at 95% confidence level. Exclusion limits are also presented considering different scenarios for the mass ratio between N and W-R, as a function of W-R mass. In the second model, pair production of third-generation scalar leptoquarks that decay into bb is considered, resulting in an observed exclusion region with leptoquark masses below 1.02 TeV, assuming a 100% branching fraction for the leptoquark decay to a lepton and a bottom quark. These results represent the most stringent limits to date on these models.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    A search for physics beyond the standard model in events with one or more high-momentum Higgs bosons, H, decaying to pairs of b quarks in association with missing transverse momentum is presented. The data, corresponding to an integrated luminosity of 35.9 fb(-1), were collected with the CMS detector at the LHC in proton-proton collisions at the center-of-mass energy root s = 13 TeV. The analysis utilizes a new b quark tagging technique based on jet substructure to identify jets from H -> b (b) over bar. Events are categorized by the multiplicity of H-tagged jets, jet mass, and the missing transverse momentum. No significant deviation from standard model expectations is observed. In the context of supersymmetry (SUSY), limits on the cross sections of pair-produced gluinos are set, assuming that gluinos decay to quark pairs, H (or Z), and the lightest SUSY particle, LSP, through an intermediate next-to-lightest SUSY particle, NLSP. With large mass splitting between the NLSP and LSP, and 100% NLSP branching fraction to H, the lower limit on the gluino mass is found to be 2010 GeV.
  • The CMS collaboration; Eerola, P.; Forthomme, L.; Kirschenmann, H.; Osterberg, K.; Voutilainen, M.; Garcia, F.; Havukainen, J.; Heikkila, J. K.; Jarvinen, T.; Kim, M. S.; Kinnunen, R.; Lampen, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Linden, T.; Luukka, P.; Maenpaa, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, J.; Pekkanen, J.; Sirunyan, A. M.; Tumasyan, A.; Tuuva, T. (2020)
    The standard model (SM) production of four top quarks (tt over bar tt over ba 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 tt over bar tt over bar signal are respectively 2.6 and 2.7 standard deviations, and the tt over bar tt over bar 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, yielding a limit of <1. 7 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. 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.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    Results are reported from a search for physics beyond the standard model in proton-proton collisions at a center-of-mass energy of root s=13TeV. The search uses a signature of a single lepton, large jet and bottom quark jet multiplicities, and high sum of large-radius jet masses, without any requirement on the missing transverse momentum in an event. The data sample corresponds to an integrated luminosity of 35.9 fb(-1) recorded by the CMS experiment at the LHC. No significant excess beyond the prediction from standard model processes is observed. The results are interpreted in terms of upper limits on the production cross section for R-parity violating supersymmetric extensions of the standard model using a benchmark model of gluino pair production, in which each gluino decays promptly via (g) over tilde -> tbs. Gluinos with a mass below 1610 GeV are excluded at 95% confidence level. (c) 2018 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    A search is presented for resonant production of second-generation sleptons ((mu) over tilde (L),(nu) over tilde (mu)) via the R-parityviolating coupling. gimel'(211) to quarks, in events with two samesign muons and at least two jets in the final state. The smuon ( muon sneutrino) is expected to decay into amuon and a neutralino (chargino), which will then decay into a second muon and at least two jets. The analysis is based on the 2016 data set of proton- proton collisions at root s = 13 TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9 fb(-1). No significant deviation is observed with respect to standard model expectations. Upper limits on cross sections, ranging from 0.24 to 730 fb, are derived in the context of two simplified models representing the dominant signal contributions leading to a same- sign muon pair. The cross section limits are translated into coupling limits for a modified constrained minimal supersymmetric model with. gimel'(211) as the only nonzero R-parity violating coupling. The results significantly extend restrictions of the parameter space compared with previous searches for similar models.
  • The CMS collaboration; Sirunyan, A. M.; Tumasyan, A.; Eerola, P.; Forthomme, Laurent; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Brücken, Erik; Garcia, F.; Havukainen, J.; Karimäki, V.; Kim, Minsuk; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Pekkanen, Juska; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, Jussi; Tuuva, T. (2021)
    A search for leptoquarks produced singly and in pairs in proton-proton collisions is presented. We consider the leptoquark (LQ) to be a scalar particle of charge -1/3e coupling to a top quark plus a tau lepton (t tau) or a bottom quark plus a neutrino (b nu), or a vector particle of charge +2/3e, coupling to t nu or b tau. These choices are motivated by models that can explain a series of anomalies observed in the measurement of B meson decays. In this analysis the signatures t tau nu b and t tau nu are probed, using data recorded by the CMS experiment at the CERN LHC at root s = 13 TeV and that correspond to an integrated luminosity of 137 fb(-1). These signatures have not been previously explored in a dedicated search. The data are found to be in agreement with the standard model prediction. Lower limits at 95% confidence level are set on the LQ mass in the range 0.98-1.73 TeV, depending on the LQ spin and its coupling lambda to a lepton and a quark, and assuming equal couplings for the two LQ decay modes considered. These are the most stringent constraints to date on the existence of leptoquarks in this scenario. (C) 2021 The Author(s). Published by Elsevier B.V.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    A search for standard model production of four top quarks (t (t) over bart (t) over bar) is reported using events containing at least three leptons (e, mu) or a same-sign lepton pair. The events are produced in proton-proton collisions at a center-of-mass energy of 13 TeVat the LHC, and the data sample, recorded in 2016, corresponds to an integrated luminosity of 35.9 fb(-1). Jet multiplicity and flavor are used to enhance signal sensitivity, and dedicated control regions are used to constrain the dominant backgrounds. The observed and expected signal significances are, respectively, 1.6 and 1.0 standard deviations, and the t (t) over bart (t) over bar cross section ismeasured to be 16.9(-11.4)(+13.8) fb, in agreement with next-to-leading-order standard model predictions. These results are also used to constrain the Yukawa coupling between the top quark and the Higgs boson to be less than 2.1 times its expected standard model value at 95% confidence level.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    A search for direct production of the supersymmetric (SUSY) partners of electrons or muons is presented in final states with two opposite-charge, same-flavour leptons (electrons and muons), no jets, and large missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb−1 of proton-proton collisions at √s = 13 TeV, collected with the CMS detector at the LHC in 2016. The search uses the MT2 variable, which generalises the transverse mass for systems with two invisible objects and provides a discrimination against standard model backgrounds containing W bosons. The observed yields are consistent with the expectations from the standard model. The search is interpreted in the context of simplified SUSY models and probes slepton masses up to approximately 290, 400, and 450GeV, assuming right-handed only, left-handed only, and both right- and left-handed sleptons (mass degenerate selectrons and smuons), and a massless lightest supersymmetric particle. Limits are also set on selectrons and smuons separately. These limits show an improvement on the existing limits of approximately 150GeV.© 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2019)
    A search for supersymmetry is presented based on events with at least one photon, jets, and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 35.9 fb -1 and were recorded at the LHC with the CMS detector in 2016. The analysis characterizes signal-like events by categorizing the data into various signal regions based on the number of jets, the number of b-tagged jets, and the missing transverse momentum. No significant excess of events is observed with respect to the expectations from standard model processes. Limits are placed on the gluino and top squark pair production cross sections using several simplified models of supersymmetric particle production with gauge-mediated supersymmetry breaking. Depending on the model and the mass of the nextto-lightest supersymmetric particle, the production of gluinos with masses as large as 2120 GeV and the production of top squarks with masses as large as 1230 GeV are excluded at 95% confidence level.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T. (2018)
    A search for the electroweak production of supersymmetric particles in protonproton collisions at a center-of-mass energy of 13TeV is presented in final states with a tau lepton pair. Both hadronic and leptonic decay modes are considered for the tau leptons. Scenarios involving the direct pair production of tau sleptons, or their indirect production via the decays of charginos and neutralinos, are investigated. The data correspond to an integrated luminosity of 35: 9 fb collected with the CMS detector in 2016. The observed number of events is consistent with the standard model background expectation. The results are interpreted as upper limits on the cross section for tau slepton pair production in di ff erent scenarios. The strongest limits are observed in the scenario of a purely left-handed low mass tau slepton decaying to a nearly massless neutralino. Exclusion limits are also set in the context of simpli fi ed models of chargino-neutralino and chargino pair production with decays to tau leptons, and range up to 710 and 630 GeV, respectively.
  • The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Talvitie, J.; Tuuva, T. (2018)
    Results are presented from a search for supersymmetry in events with a single electron or muon and hadronic jets. The data correspond to a sample of proton-proton collisions at root s = 13 TeV with an integrated luminosity of 35.9 fb(-1), recorded in 2016 by the CMS experiment. A number of exclusive search regions are defined according to the number of jets, the number of b-tagged jets, the scalar sum of the transverse momenta of the jets, and the scalar sum of the missing transverse momentum and the transverse momentum of the lepton. Standard model background events are reduced significantly by requiring a large azimuthal angle between the direction of the lepton and of the reconstructed W boson, computed under the hypothesis that all of the missing transverse momentum in the event arises from a neutrino produced in the leptonic decay of the W boson. The numbers of observed events are consistent with the expectations from standard model processes, and the results are used to set lower limits on supersymmetric particle masses in the context of two simplified models of gluino pair production. In the first model, where each gluino decays to a top quark-antiquark pair and a neutralino, gluino masses up to 1.8 TeV are excluded at the 95% CL. The second model considers a three-body decay to a light quark-antiquark pair and a chargino, which subsequently decays to a W boson and a neutralino. In this model, gluinos are excluded up to 1.9 TeV. (C) 2018 The Author. Published by Elsevier B.V.