ATLAS

Abstract:

Results are presented from a search for physics beyond the standard model based on events with large missing transverse energy, at least three jets, and at least one, two, or three b-quark jets. The study is performed using a sample of proton-proton collision data collected at √s=7TeV with the CMS detector at the LHC in 2011. The integrated luminosity of the sample is 4.98fb -1. The observed number of events is found to be consistent with the standard model expectation, which is evaluated using control samples in the data. The results are used to constrain cross sections for the production of supersymmetric particles decaying to b-quark-enriched final states in the context of simplified model spectra. © 2012 CERN. Published by the American Physical Society.

Abstract:

We report a measurement of the bottom-strange meson mixing phase βs using the time evolution of Bs0→J/ ψ(→μ+μ-)(→K+K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at √s=1.96TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6fb -1 of integrated luminosity. We report confidence regions in the two-dimensional space of βs and the Bs0 decay-width difference ΔΓs and measure βs [-π/2,-1.51] [-0.06,0.30] [1.26,π/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of βs, we also determine ΔΓs=0.068±0. 026(stat)±0.009(syst)ps-1 and the mean Bs0 lifetime τs=1.528±0.019(stat)±0.009(syst)ps, which are consistent and competitive with determinations by other experiments. © 2012 American Physical Society.