Measurement of the t anti-t Production Cross Section in p anti-p Collisions at s**(1/2) = 1.96 TeV using Missing E(t) + jets Events with Secondary Vertex b-Tagging

We present a measurement of the t anti-t production cross section in p anti-p collisions at s**(1/2) = 1.96 TeV which uses events with an inclusive signature of significant missing transverse energy and jets. This is the first measurement which makes no explicit lepton identification requirements, so that sensitivity to W --> tau nu decays is maintained. Heavy flavor jets from top quark decay are identified with a secondary vertex tagging algorithm. From 311 pb-1 of data collected by the Collider Detector at Fermilab we measure a production cross section of 5.8 +/- 1.2(stat.)+0.9_-0.7(syst.) pb for a top quark mass of 178 GeV/c2, in agreement with previous determinations and standard model predictions.Comment: 7 pages, 4 figures, submitted to Phys. Rev. Let

Search for New Color-Octet Vector Particle Decaying to ttbar in ppbar Collisions at s=1.96\sqrt{s}=1.96 TeV

Submitted to Phys. Lett. BWe present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton-antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb$^{-1}$ of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study $t\bar{t}$ events in the lepton+jets channel with at least one $b$-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV$/c^2$ and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.We present the result of a search for a massive color-octet vector particle, (e.g. a massive gluon) decaying to a pair of top quarks in proton–antiproton collisions with a center-of-mass energy of 1.96 TeV. This search is based on 1.9 fb−1 of data collected using the CDF detector during Run II of the Tevatron at Fermilab. We study View the MathML source events in the lepton + jets channel with at least one b-tagged jet. A massive gluon is characterized by its mass, decay width, and the strength of its coupling to quarks. These parameters are determined according to the observed invariant mass distribution of top quark pairs. We set limits on the massive gluon coupling strength for masses between 400 and 800 GeV/c2 and width-to-mass ratios between 0.05 and 0.50. The coupling strength of the hypothetical massive gluon to quarks is consistent with zero within the explored parameter space.Peer reviewe

Search for decays of B-0 mesons into e(+)e(-), mu(+)mu(-) and e(+/-)mu(-/+) final states

We present a search for the decays B-0 -> e(+)e(-), B-0 ->mu(+)mu(-), and B-0 -> e(+/-)mu(-/+) using data collected with the BABAR detector at the PEP-II e(+)e(-) collider at SLAC. Using a data set corresponding to 384x10(6) B (B) over bar pairs, we do not find evidence of any of the three decay modes. We obtain upper limit on the branching fractions, at 90% confidence level, of B(B-0 -> e(+)e(-))mu(+)mu(-)) e(+/-)mu(-/+))< 9.2x10(-8)

Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV using lepton plus jets events with jet probability b-tagging

We present a measurement of the t (t) over bar production cross section using events with one charged lepton and jets from p (p) over bar collisions at a center-of-mass energy of 1.96 TeV. A b-tagging algorithm based on the probability of displaced tracks coming from the event interaction vertex is applied to identify b quarks from top decay. Using 318 pb(-1) of data collected with the CDF II detector, we measure the t (t) over bar production cross section in events with at least one restrictive (tight) b-tagged jet and obtain 8.9(-1.0)(+1.0)(stat)(-1.0)(+1.1)(syst) pb. The cross section value assumes a top quark mass of m(t)=178 GeV/c(2) in the acceptance corrections. The dependence of the cross section on m(t) is presented in the paper. This result is consistent with other CDF measurements of the t (t) over bar cross section using different samples and analysis techniques, and has similar systematic uncertainties. We have also performed consistency checks by using the b-tagging probability function to vary the signal-to-background ratio and also using events that have at least two b-tagged jets. RI Ruiz, Alberto/E-4473-2011; Robson, Aidan/G-1087-2011; De Cecco, Sandro/B-1016-2012; St.Denis, Richard/C-8997-2012; Prokoshin, Fedor/E-2795-2012; Azzi, Patrizia/H-5404-201

The CMS experiment at the CERN LHC

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