Heavy-Flavor Results from CMS

Heavy-flavor physics offers the opportunity to make indirect tests of physics beyond the Standard Model through precision measurements, and of quantum chromodynamics (QCD) through particle production studies. The rare decays B0s, B0 and D0 to dimuon final states are excellent tests of the flavor sector of the Standard Model and are sensitive to new physics. We report on studies of these decays and present the first observation of the excited b baryon Xib*0 in strong decays to Xib and a charged pion, the observation of two Bc meson decay modes and production properties of the Lambda_b baryon, all performed with the CMS experiment in pp collisions at sqrt(s) = 7 TeV.Comment: Submitted as written proceedings for a talk given at the 2012 International Conference on High Energy Physics (ICHEP 2012), Melbourne, Australi

Quarkonium Production with the CMS Experiment

Results from studies of quarkonium production are presented from the CMS experiment at the LHC in proton-proton collisions at sqrt(s) = 7 TeV. We report measurements of the ratio of chi_c2/chi_c1 production versus transverse momentum and Upsilon(nS) production vs rapidity and transverse momentum for the 1S, 2S and 3S states. Reconstruction of Bc mesons is also presented in two decay channels.Comment: Submitted as written proceedings for a talk given at the 2012 International Conference on High Energy Physics (ICHEP 2012), Melbourne, Australi

Future Sensitivity Studies for Supersymmetry Searches at CMS at 14 TeV

The sensitivity for CMS searches for supersymmetry is evaluated in the context of an upgraded LHC at a center-of-mass energy of 14 TeV and an integrated luminosity of 300 fb-1. Results for several key searches for supersymmetry are presented including direct and gluino-mediated stop and sbottom production and electroweak production of supersymmetric particles.Comment: Presentation at the DPF 2013 Meeting of the American Physical Society Division of Particles and Fields, Santa Cruz, California, August 13-17, 201

Performance of the CMS tracking detectors from the 2009 LHC run

The 2009 run provided the first proton-proton collisions from the Large Hadron Collider (LHC) at center of mass energies of 900 GeV and 2.36 TeV. The Compact Muon Solenoid (CMS) experiment has recorded a large sample of minimum bias events from these collisions. We present results from the all silicon tracking detectors from this run. The performance of the tracker and track reconstruction algorithms are considered including signal-to-noise, efficiencies and comparisons to simulation for track parameter and resonance reconstruction performance.Comment: 4 pages, 3 figures, proceedings from the 2010 Lake Louise Winter Institut

Study of Rare B Meson Decays Related to the CKM Angle Beta at BaBar

This study reports measurements of the branching fractions of B meson decays to {eta}{prime}K{sup +}, {eta}{prime}K{sup 0}, {omega}{pi}{sup +}, {omega}K{sup +}, and {omega}K{sup 0}. Charge asymmetries are measured for the charged modes and the time-dependent CP-violation parameters S and C are measured for the neutral modes. The results are based on a data sample of 347 fb{sup -1} containing 383 million B{bar B} pairs recorded by the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring located at the Stanford Linear Accelerator Center. Statistically significant signals are observed for all channels with the following results: B(B{sup +} {yields} {eta}{prime}K{sup +}) = (70.0{+-}1.5{+-}2.8)x10{sup -6}, B(B{sup 0} {yields} {eta}{prime}K{sup 0}) = (66.6{+-}2.6{+-}2.8)x10{sup -6}, B(B{sup +} {yields} {omega}{pi}{sup +}) = (6.7{+-}0.5{+-}0.4)x10{sup -6}, B(B{sup +} {yields} {omega}K{sup +}) = (6.3{+-}0.5{+-}0.3)x10-6, and B(B{sup 0} {yields} ?K0) = (5.6{+-}0.8{+-}0.3)x10-6, where the first uncertainty is statistical and the second is systematic. We measure A{sub ch}({eta}{prime}K{sup +}) = +0.010{+-}0.022{+-}0.006, A{sub ch}({omega}{pi}{sup +}) = -0.02{+-}0.08{+-}0.01, A{sub ch}({omega}K{sup +}) = -0.01{+-}0.07{+-}0.01, S{sub {eta}{prime}K{sup 0}{sub S}} = 0.56{+-}0.12{+-}0.02, C{sub {eta}{prime}K{sup 0}{sub S}} = -0.24 {+-} 0.08 {+-} 0.03, S{sub {omega}{prime}K{sup 0}{sub S}} = 0.62+0.25 -0.29 {+-} 0.02, and C{sub {omega}{prime}K{sup 0}{sub S}} = -0.39+0.25 -0.24 {+-} 0.03. The result in S{sub {eta}{prime}K{sup 0}{sub S}} contributes to the published measurement from BABAR, which differs from zero by 5.5 standard deviations and is the first observation of mixing-induced CP-violation in a charmless B decay

Study of quark and gluon jet substructure in Z plus jet and dijet events from pp collisions

Measurements of jet substructure describing the composition of quark- and gluon-initiated jets are presented. Proton-proton (pp) collision data at s&radic; = 13 TeV collected with the CMS detector are used, corresponding to an integrated luminosity of 35.9 fb&minus;1. Generalized angularities are measured that characterize the jet substructure and distinguish quark- and gluon-initiated jets. These observables are sensitive to the distributions of transverse momenta and angular distances within a jet. The analysis is performed using a data sample of dijet events enriched in gluon-initiated jets, and, for the first time, a Z+jet event sample enriched in quark-initiated jets. The observables are measured in bins of jet transverse momentum, and as a function of the jet radius parameter. Each measurement is repeated applying a &ldquo;soft drop&rdquo; grooming procedure that removes soft and large angle radiation from the jet. Using these measurements, the ability of various models to describe jet substructure is assessed, showing a clear need for improvements in Monte Carlo generators.</p

Search for long-lived particles produced in association with a Z boson in proton-proton collisions at root s=13 TeV

A search for long-lived particles (LLPs) produced in association with a Z boson is presented. The study is performed using data from proton-proton collisions with a center-of-mass energy of 13 TeV recorded by the CMS experiment during 2016&ndash;2018, corresponding to an integrated luminosity of 117 fb&minus;1. The LLPs are assumed to decay to a pair of standard model quarks that are identified as displaced jets within the CMS tracker system. Triggers and selections based on Z boson decays to electron or muon pairs improve the sensitivity to light LLPs (down to 15 GeV). This search provides sensitivity to beyond the standard model scenarios which predict LLPs produced in association with a Z boson. In particular, the results are interpreted in the context of exotic decays of the Higgs boson to a pair of scalar LLPs (H &rarr; SS). The Higgs boson decay branching fraction is constrained to values less than 6% for proper decay lengths of 10&ndash;100 mm and for LLP masses between 40 and 55 GeV. In the case of low-mass (&asymp; 15 GeV) scalar particles that subsequently decay to a pair of b quarks, the search is sensitive to branching fractions B(H &rarr; SS) &lt; 20% for proper decay lengths of 10&ndash;50 mm. The use of associated production with a Z boson increases the sensitivity to low-mass LLPs of this analysis with respect to gluon fusion searches. In the case of 15 GeV scalar LLPs, the improvement corresponds to a factor of 2 at a proper decay length of 30 mm.</p