Results of recent Higgs boson and beyond standard model searches in CMS performed with datasets of 1.0 - 1.7 fb-1 will be summarized in this proceeding contributed to the 41st International Symposium on Multiparticle Dynamics (ISMD2011).
Prospective searches about Higgs physics and beyond the Standard Model are presented for the CMS and ATLAS experiments. Possible excesses of events in real data could be an indication of the existence of new particles, even with few hundred pb-1 of integrated luminosity. In this paper the focus is on the current analyses strategies and on the potential both for a discovery and/or for an exclusion of the Standard Model Higgs boson in the main decay channels. The searches for some supersymmetric and exotic particles predicted by several theoretical models are also discussed.
We present the potential for discovering the Standard Model Higgs boson produced by the vector-boson fusion mechanism. We considered the decay of Higgs bosons into the W+W- final state, with both W-bosons subsequently decaying leptonically. The main background is ttbar with one or more jets produced. This study is based on a full simulation of the CMS detector, and up-to-date reconstruction codes. The result is that a signal of 5 sigma significance can be obtained with an integrated luminosity of 12-72 1/fb for Higgs boson masses between 130-200 GeV. In addition, the major background can be measured directly to 7% from the data with an integrated luminosity of 30 1/fb. In this study, we also suggested a method to obtain information in Higgs mass using the transverse mass distributions.
We present a search for the standard model Higgs boson production in association with a $W$ boson in proton-antiproton collisions ($pbar{p}rightarrow W^pm H rightarrow ell u bbar{b}$) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector which correspond to an integrated luminosity of approximately 2.7 fb$^{-1}$. We recorded this data with two kinds of triggers. The first kind required high-p$_T$ charged leptons and the second required both missing transverse energy and jets. The search selects events consistent with a signature of a single lepton ($e^pm/mu^pm$), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method and a jet probability tagging method. Kinematic information is fed in an artificial neural network to improve discrimination between signal and background. The search finds that both the observed number of events and the neural network output distributions are consistent with the standard model background expectations, and sets 95% confidence level upper limits on the production cross section times branching ratio. The limits are expressed as a ratio to the standard model production rate. The limits range from 3.6 (4.3 expected) to 61.1 (43.2 expected) for Higgs masses from 100 to 150 GeV/$c^{2}$, respectively.
A recent preliminary investigation based on Durguts report at the American Physical Society site shows a structure at $18.4~ {rm GeV}$ exists in the invariant mass distribution of $Upsilon l^+l^- ~ (l = e,, mu)$ at the LHC center-of-mass energy of $7$ and $8~ {rm TeV}$. Its appearance attracts attention of theorists and experimentalists of high energy physics, because it might be a Higgs-like boson of $18.4~ {rm GeV}$ which would serve as a signal of the new physics beyond the Standard Model. We have carried out computations on the corresponding quantities (production and decay rates) based on quantum field theory and compared the results with experimental data. Our numerical results do not support the assertion that the $18.4~ {rm GeV}$ peak corresponds to a neutral $0^{++}$ boson which decays into $Upsilon l^+l^-$. Much further works (both experimental and theoretical) are badly needed.
Models of Beyond the Standard Model (BSM) physics, like the Minimal Supersymmetric Standard Model (MSSM), often involve an extended Higgs sector, giving rise to extra neutral or charged Higgs bosons. The discovery reach expected from simulation studies for such additional Higgs particles is presented for the ATLAS, CMS and FP420 detectors at the LHC. Emphasis is put on production and decay modes involving heavy flavour b and tau particles, which are enhanced in large regions of BSM parameter space. The LHC experiments are indeed particularly well equipped to tackle final states containing heavy flavour.