Search for supersymmetry in events with b jets and missing transverse momentum at the LHC

A search for supersymmetry is presented using a sample of events with b jets and missing transverse momentum. The search uses a data sample of proton-proton collisions at a centre-of-mass energy of 7TeV, corresponding to an integrated luminosity of 35 pb(-1), collected with the CMS detector. A total of 0.33(-0.33)(+0.43) (stat.) +/- 0.13 (syst.) events is predicted, using control samples in the data, to arise from standard model processes, and one event is observed in the data. Upper limits are set at the 95% confidence level on the cross sections of benchmark supersymmetric models

Long-range and short-range dihadron angular correlations in central PbPb collisions at √sNN=2.76 TeV

This is the pre-print version of the Published Article, which can be accessed from the link below.First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76TeV over a broad range in relative pseudorapidity ( ) and the full range of relative azimuthal angle ( ). The data were collected with the CMS detector, at the LHC. A broadening of the away-side ( ) azimuthal correlation is observed at all , as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in are observed for particles with similar values. This phenomenon, also known as the \ridge", persists up to at least j j = 4. For particles with transverse momenta (pT) of 2-4 GeV/c, the ridge is found to be most prominent when these particles are correlated with particles of pT = 2-6 GeV/c, and to be much reduced when paired with particles of pT = 10-12 GeV/c

Search for a WbosondecayingtoamuonandaneutrinoinW^ boson decaying to a muon and a neutrino in ppcollisionsat collisions at s = 7$ TeV

A new heavy gauge boson, W′, decaying to a muon and a neutrino, is searched for in pp collisions at a centre-of-mass energy of 7 TeV. The data, collected with the CMS detector at the LHC, correspond to an integrated luminosity of 36 pb−1. No significant excess of events above the standard model expectation is found in the transverse mass distribution of the muon–neutrino system. Masses below 1.40 TeV are excluded at the 95% confidence level for a sequential standard-model-like W′. The W′ mass lower limit increases to 1.58 TeV when the present analysis is combined with the CMS result for the electron channe

Observation of a new boson with mass near 125 GeV in pp collisions at s\sqrt{s} = 7 and 8 TeV

A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 inverse femtobarns at $\sqrt{s}$ = 7 TeV, and up to 5.3 inverse femtobarns at $\sqrt{s}$ = 8 TeV. The results for five Higgs boson decay modes $\gamma\gamma, ZZ, WW, \tau \tau$, and bb, which show a combined local significance of 5 standard deviations near 125 GeV, are reviewed. A fit to the invariant mass of the two high resolution channels, gamma gamma and ZZ to 4 ell, gives a mass estimate of 125.3 +/- 0.4 (stat) +/- 0.5 (syst) GeV. The measurements are interpreted in the context of the standard model Lagrangian for the scalar Higgs field interacting with fermions and vector bosons. The measured values of the corresponding couplings are compared to the standard model predictions. The hypothesis of custodial symmetry is tested through the measurement of the ratio of the couplings to the W and Z bosons. All the results are consistent, within their uncertainties, with the expectations for a standard model Higgs boson.Peer Reviewe

Search for heavy long-lived charged particles in pp collisions at root s=7 TeV

The result of a search for heavy long-lived charged particles produced in pp collisions at √s=7 TeV at the LHC is described. The data sample has been collected using the CMS detector and corresponds to an integrated luminosity of 5.0 fb -1. The inner tracking detectors are used to define a sample of events containing tracks with high momentum and high ionization energy loss. A second sample of events, which have high-momentum tracks satisfying muon identification requirements in addition to meeting high-ionization and long time-of-flight requirements, is analyzed independently. In both cases, the results are consistent with the expected background estimated from data. The results are used to establish cross section limits as a function of mass within the context of models with long-lived gluinos, scalar top quarks and scalar taus. Cross section limits on hyper-meson particles, containing new elementary long-lived hyper-quarks predicted by a vector-like confinement model, are also presented. Lower limits at 95% confidence level on the mass of gluinos (scalar top quarks) are found to be 1098 (737) GeV/c 2. A limit of 928 (626) GeV/c 2 is set for a gluino (scalar top quark) that hadronizes into a neutral bound state before reaching the muon detectors. The lower mass limit for a pair produced scalar tau is found to be 223 GeV/c 2. Mass limits for a hyper-kaon are placed at 484, 602, and 747 GeV/c 2 for hyper-ρ masses of 800, 1200, and 1600 GeV/c 2, respectively. © 2012 CERN

Search for a heavy bottom-like quark in pp collisions at root s=7 TeV

A search for pair-produced bottom-like quarks in pp collisions at root s = 7 TeV is conducted with the CMS experiment at the LHC. The decay b' -> tW is considered in this search. The b'(b) over bar' tW-(t) over barW(+) process can be identified by the distinctive signature of trileptons and same-sign dileptons. With a data sample corresponding to an integrated luminosity of 34 pb(-1), no excess above the standard model background predictions is observed and a b' quark with a mass between 255 and 361 GeV/c(2) is excluded at the 95% confidence level. (C) 2011 CERN. Published by Elsevier B.V. All rights reserved