Quasi-Model-Independent Search for New High pT Physics at D0

Physics Letters B, 2012

AA (), AB (), AC (), AD (), AE (Universiteit Antwerpen, Antwerpen, Belgium), AF (), AG (), AH (), AI (), AJ (), AK (), AL (), AM (), AN (), AO (), AP (), AQ (), AR (), AS (), AT (), AU (), AV (), AW (), AX (), AY (), AZ (), BA (), BB (), BC (), BD (), BE (), BF (), BG (), BH (), BI (E. Andronikashvili Institute of Physics, Academy of Science, Tbilisi, Georgia), BJ (), BK (), BL (), BM (Deutsches Elektronen-Synchrotron, Hamburg, Germany), BN (), BO (), BP (), BQ (), BR (), BS (), BT (), BU (), BV (), BW (), BX (), BY (), BZ (), CA (), CB (), CC (), CD (), CE (), CF (), CG (), CH (), CI ...

A search is presented for physics beyond the standard model in final states with two opposite-sign same-flavor leptons, jets, and missing transverse momentum. The data sample corresponds to an integrated luminosity of 19.4 fb −1 of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the CERN LHC in 2012. The analysis focuses on searches for a kinematic edge in the invariant mass distribution of the opposite-sign same-flavor lepton pair and for final states with an on-shell Z boson. The observations are consistent with expectations from standard model processes and are interpreted in terms of upper limits on the production of supersymmetric particles.

2013

This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an integrated luminosity of 5:0 fb À1 at ffiffi ffi s p ¼ 7 TeV, and a further 3:7 fb À1 at ffiffi ffi s p ¼ 8 TeV. No evidence is found for an excess. The results are interpreted in terms of limits on a heavy charged gauge boson (W 0) in the sequential standard model, a split universal extra dimension model, and contact interactions in the helicity-nonconserving model. For the last, values of the binding energy below 10.5 (8.8) TeV in the electron (muon) channel are excluded at a 95% confidence level. Interpreting the ' final state in terms of a heavy W 0 with standard model couplings, masses below 2.90 TeV are excluded.

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy √ s = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 fb −1 . Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper. T and hadronic energy, while the counting experiments do not as-2 3 Event Selection sume a specific dilepton production mechanism and are also sensitive to BSM scenarios that produce lepton pairs with uncorrelated flavor.

Physical Review D, 2012

2012

A search is presented for physics beyond the standard model (BSM) in final states with a pair of opposite-sign isolated leptons accompanied by jets and missing transverse energy. The search uses LHC data recorded at a center-of-mass energy √ s = 7 TeV with the CMS detector, corresponding to an integrated luminosity of approximately 5 fb −1 . Two complementary search strategies are employed. The first probes models with a specific dilepton production mechanism that leads to a characteristic kinematic edge in the dilepton mass distribution. The second strategy probes models of dilepton production with heavy, colored objects that decay to final states including invisible particles, leading to very large hadronic activity and missing transverse energy. No evidence for an event yield in excess of the standard model expectations is found. Upper limits on the BSM contributions to the signal regions are deduced from the results, which are used to exclude a region of the parameter space of the constrained minimal supersymmetric extension of the standard model. Additional information related to detector efficiencies and response is provided to allow testing specific models of BSM physics not considered in this paper. T and hadronic energy, while the counting experiments do not as-2 3 Event Selection sume a specific dilepton production mechanism and are also sensitive to BSM scenarios that produce lepton pairs with uncorrelated flavor.

Physical Review D, 2015

A search for new physics in proton-proton collisions having final states with an electron or muon and missing transverse energy is presented. The analysis uses data collected in 2012 with the CMS detector, at an LHC center-of-mass energy of 8 TeV, and corresponding to an integrated luminosity of 19.7 fb −1. No significant deviation of the transverse mass distribution of the charged lepton-neutrino system from the standard model prediction is found. Mass exclusion limits of up to 3.28 TeV at 95% confidence level for a W boson with the same couplings as that of the standard model W boson are determined. Results are also derived in the framework of split universal extra dimensions, and exclusion limits on Kaluza-Klein W (2) KK states are found. The final state with large missing transverse energy also enables a search for dark matter production with a recoiling W boson, with limits set on the mass and the production cross section of potential candidates. Finally, limits are established for a model including interference between a left-handed W boson and the standard model W boson, and for a compositeness model.

Journal of High Energy Physics, 2013

A search for physics beyond the standard model involving events with one or more photons, jets, and missing transverse energy has been performed by the CMS experiment. The data sample corresponds to an integrated luminosity of 4.93 fb −1 of protonproton collisions at √ s = 7 TeV, produced at the Large Hadron Collider. No excess of events with large missing transverse energy is observed beyond expectations from standard model processes, and upper limits on the signal production cross sections for new physics processes are set at the 95% confidence level. The results of this search are interpreted in the context of three models of new physics: a general model of gauge-mediated supersymmetry breaking, Simplified Models, and a theory involving universal extra dimensions. In the absence of evidence for new physics, exclusion regions are derived in the parameter spaces of the respective models.

Physical Review Letters, 1991

Physical Review D, 2013

This Letter describes the search for an enhanced production rate of events with a charged lepton and a neutrino in high-energy pp collisions at the LHC. The analysis uses data collected with the CMS detector, with an integrated luminosity of 5:0 fb À1 at ffiffi ffi s p ¼ 7 TeV, and a further 3:7 fb À1 at ffiffi ffi s p ¼ 8 TeV. No evidence is found for an excess. The results are interpreted in terms of limits on a heavy charged gauge boson (W 0) in the sequential standard model, a split universal extra dimension model, and contact interactions in the helicity-nonconserving model. For the last, values of the binding energy below 10.5 (8.8) TeV in the electron (muon) channel are excluded at a 95% confidence level. Interpreting the ' final state in terms of a heavy W 0 with standard model couplings, masses below 2.90 TeV are excluded.