Results are presented from searches for the standard model Higgs boson in proton-proton collisions at root s = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 fb(-1) at 7 TeV and 5.3 fb(-1) at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, W+W-, tau(+)tau(-), and b (b) over bar. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, gamma gamma and ZZ; a fit to these signals gives a mass of 125.3 +/- 0.4(stat.) +/- 0.5(syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved
Recent results of the searches for Supersymmetry in final states with one or two leptons at CMS are presented. Many Supersymmetry scenarios, including the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM), predict a substantial amount of events containing leptons, while the largest fraction of Standard Model background events -which are QCD interactions -gets strongly reduced by requiring isolated leptons. The analyzed data was taken in 2011 and corresponds to an integrated luminosity of approximately L = 1 fb −1 . The center-of-mass energy of the pp collisions was √ s = 7 TeV.
This work summarizes and puts in an overall perspective studies done within CMS concerning the discovery potential for squarks and gluinos, sleptons, charginos and neutralinos, SUSY dark matter, lightest Higgs, sparticle mass determination methods and the detector design optimisation in view of SUSY searches. It represents the status of our understanding of these subjects as of Summer 1997.As a benchmark model we used the minimal supergravity-inspired supersymmetric standard model (mSUGRA) with a stable LSP. Discovery of supersymmetry at the LHC should be relatively straightforward. It may occur through the observation of a large excesses of events in missing E T plus jets, or with one or more isolated leptons. An excess of trilepton events or of isolated dileptons with missing E T , exhibiting a characteristic signature in the l + l − invariant mass distribution could also be the first manifestation of SUSY production. Squarks and gluinos can be discovered for masses in excess of 2 TeV. Charginos and neutralinos can be discovered from an excess of events in dilepton or trilepton final states. Inclusive searches can give early indications from their copious production in squark and gluino cascade decays. Indirect evidence for sleptons can be obtained also from inclusive dilepton studies. Isolation requirements and a jet veto would allow detection of both, the direct chargino/neutralino production and of directly-produced sleptons. Squark and gluino production may also represent a copious source of Higgs bosons through cascade decays. The lightest SUSY Higgs h → bb may be reconstructed with a signal/background ratio of order 1 thanks to hard cuts on E miss T justified by escaping LSP's. The lightest supersymmetric particle of SUSY models with conserved R-parity represents a very good candidate for the cosmological dark matter. The region of parameter space where this is true is well-covered by our searches, at least for tanβ = 2.If supersymmetry exists at electroweak scale it could hardly escape detection in CMS, and the study of supersymmetry will form a central part of our physics program.
This work summarizes the studies for the Higgs boson searches in CMS at the LHC collider. The main discovery channels are presented and the potential is given for the discovery of the SM Higgs boson and the Higgs bosons of the MSSM. The phenomenology, detector, trigger and reconstruction issues are briefly discussed. h scenario, this choice leads to a small deviation in m h and in the final event rates for a given tanβ. The top mass is set to 175 GeV/c 2 .At tree level the h(H) mass is bound to be below(above) the Z boson mass but the radiative corrections, proportional to m 4 top , bring the upper (lower) bound to a significantly larger value. The one loop and dominant two loop calculations, with the SUSY parameters listed above, predict m h =127 GeV/c 2 for A t = 2450 GeV/c 2 and 113 GeV/c 2 for A t = 0 [2]. s42 S. Abdullin et al.: Summary of the CMS potential for the Higgs boson discovery
We discuss the SM Higgs discovery potential of LHC in the reaction pp → H + jet → γγ + jet when the jet is observed at sufficiently high E t to be reliably identified. We conclude that this channel gives promising discovery possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation at a low luminosity. With 30 fb −1 of accumulated data and for M H = 120 GeV about 100 signal events could be observed with the number of background events larger by a factor of 2 only, showing a signal significance S/ √ B ∼ 7. We use the difference of distributions in the partonic subprocess energy √ŝ for the signal and background for a better separation of the signal.
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