A search for supersymmetry with R-parity conservation in proton-proton collisions at a centre-of-mass energy of 7 TeV is presented. The data correspond to an integrated luminosity of 35 inverse picobarns collected by the CMS experiment at the LHC. The search is performed in events with jets and significant missing transverse energy, characteristic of the decays of heavy, pair-produced squarks and gluinos. The primary background, from standard model multijet production, is reduced by several orders of magnitude to a negligible level by the application of a set of robust kinematic requirements. With this selection, the data are consistent with the standard model backgrounds, namely t t-bar, W + jet and Z + jet production, which are estimated from data control samples. Limits are set on the parameters of the constrained minimal supersymmetric extension of the standard model. These limits extend those set previously by experiments at the Tevatron and LEP colliders

A search for neutral Higgs bosons in the minimal supersymmetric extension of the standard model (MSSM) decaying to tau-lepton pairs in pp collisions is performed, using events recorded by the CMS experiment at the LHC. The dataset corresponds to an integrated luminosity of 24.6 fb −1 , with 4.9 fb −1 at 7 TeV and 19.7 fb −1 at 8 TeV. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes the case where the Higgs boson is produced in association with a b-quark jet. No excess is observed in the tau-lepton-pair invariant mass spectrum. Exclusion limits are presented in the MSSM parameter space for different benchmark scenarios, m max h , m mod+ h , m mod− h , light-stop, lightstau, τ -phobic, and low-m H . Upper limits on the cross section times branching fraction for gluon fusion and b-quark associated Higgs boson production are also given. A Exclusion limits 23The CMS collaboration 37 IntroductionA broad variety of precision measurements have shown the overwhelming success of the standard model (SM) [1][2][3] of fundamental interactions, which includes an explanation for the origin of the mass of the weak force carriers, as well as for the quark and lepton masses. In the SM, this is achieved via the Brout-Englert-Higgs mechanism [4][5][6][7][8][9], which predicts the existence of a scalar boson, the Higgs boson. However, the Higgs boson mass in the SM is not protected against quadratically divergent quantum-loop corrections at high energy, known as the hierarchy problem. In the model of supersymmetry (SUSY) [10,11], which postulates a symmetry between the fundamental bosons and fermions, a cancellation of these divergences occurs naturally. The Higgs sector of the minimal supersymmetric extension of the standard model (MSSM) [12,13] The dominant neutral MSSM Higgs boson production mechanism is the gluon fusion process for small and moderate values of tan β. At large values of tan β b-quark associated production is the dominant contribution, due to the enhanced Higgs boson Yukawa coupling to b quarks. Figure 1 shows the leading-order diagrams for the gluon fusion and b-quark associated Higgs boson production, in the four-flavor and in the five-flavor scheme. In the region of large tan β the branching fraction to tau leptons is also enhanced, making the search for neutral MSSM Higgs bosons in the τ τ final state particularly interesting. This paper reports a search for neutral MSSM Higgs bosons in pp collisions at √ s = 7 TeV and 8 TeV in the τ τ decay channel. The data were recorded with the CMS detector [14] at the CERN LHC and correspond to an integrated luminosity of 24.6 fb −1 , with 4.9 fb −1 at 7 TeV and 19.7 fb −1 at 8 TeV. Five different τ τ signatures are studied, eτ h , µτ h , eµ, µµ, and τ h τ h , where τ h denotes a hadronically decaying τ . These results are an extension of previous searches by the The results are interpreted in the context of the MSSM with different benchmark scenarios described in section 1.1 and also in a model independent way, in terms of upper...

The results of comprehensive studies of missing transverse energy as measured by the CMS detector in pp collisions at a centre-of-mass energy of 7 TeV are presented. Three missing transverse energy reconstruction algorithms are deployed for various physics analyses. The scale and resolution for missing transverse energy are validated using vector boson and dijet events, and severe mismeasurements due to the detector are studied. We also parametrize the effects of multiple pp interactions within the same bunch crossings on the scale and resolution. A tool, called missing transverse energy significance, based on particle resolutions in each event is also presented.

The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods, we find evidence of statistically significant azimuthal asymmetries for charged pion pairs in e(+)e(-) annihilation at a center-of-mass energy of 10.52 GeV, which can be attributed to a transverse polarization of the primordial quarks. The measurement was performed using a sample of 79 x 10(6) hadronic events collected with the Belle detector.

The newly discovered "Higgs" boson h 0 , being lighter than the top quark t, opens up new probes for flavor and mass generation. In the general two Higgs doublet model, new ct, cc and tt Yukawa couplings could modify h 0 properties. If t → ch 0 occurs at the percent level, the observed ZZ * and γγ signal events may have accompanying cbW activity coming from tt feeddown. We suggest that t → ch 0 can be searched for via h 0 → ZZ * , γγ, W W * and bb, perhaps even τ + τ − modes in tt events. Existing data might be able to reveal some clues for t → ch 0 signature, or push the branching ratio B(t → ch 0 ) down to below the percent level.