Evidence for the exclusive decay Bc+- to J/psi pi+- and measurement of the mass of the Bc meson

We report first evidence for a fully reconstructed decay mode of the B_c^{\pm} meson in the channel B_c^{\pm} \to J/psi \pi^{\pm}, with J/psi \to mu^+mu^-. The analysis is based on an integrated luminosity of 360 pb$^{-1} in p\bar{p} collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 \pm 4.6 signal events with a background of 7.1 \pm 0.9 events, and a fit to the J/psi pi^{\pm} mass spectrum yields a B_c^{\pm} mass of 6285.7 \pm 5.3(stat) \pm 1.2(syst) MeV/c^2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%.Comment: 7 pages, 3 figures. Version 3, accepted by PR

Measurement of B(t->Wb)/B(t->Wq) at the Collider Detector at Fermilab

We present a measurement of the ratio of top-quark branching fractions R= B(t -> Wb)/B(t -> Wq), where q can be a b, s or a d quark, using lepton-plus-jets and dilepton data sets with integrated luminosity of ~162 pb^{-1} collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of t-tbar events with different multiplicity of identified secondary vertices. We set a lower limit of R > 0.61 at 95% confidence level.Comment: 7 pages, 2 figures, published in Physical Review Letters; changes made to be consistent with published versio

Measurement of the cross section for t(t)over-bar production in p(p)over-bar collisions using the kinematics of lepton plus jets events

We present a measurement of the top pair production cross section in p (p) over bar collisions at root s=1.96 TeV. We collect a data sample with an integrated luminosity of 194 +/- 11 pb(-1) with the CDF II detector at the Fermilab Tevatron. We use an artificial neural network technique to discriminate between top pair production and background processes in a sample of 519 lepton+jets events, which have one isolated energetic charged lepton, large missing transverse energy and at least three energetic jets. We measure the top pair production cross section to be sigma(t (t) over bar)=6.6 +/- 1.1 +/- 1.5 pb, where the first uncertainty is statistical and the second is systematic

Measurement of B(t -\u3e Wb)/B(t -\u3e Wq) at the Collider Detector at Fermilab

We present a measurement of the ratio of top-quark branching fractions R=B(t -\u3e Wb)/B(t -\u3e Wq), where q can be a b, s, or a d quark, using lepton-plus-jets and dilepton data sets with an integrated luminosity of similar to 162 pb(-1) collected with the Collider Detector at Fermilab during Run II of the Tevatron. The measurement is derived from the relative numbers of t (t) over bar events with different multiplicity of identified secondary vertices. We set a lower limit of R \u3e 0.61 at 95% confidence level

Evidence for B-s(0)-\u3ephi phi decay and measurements of branching ratio and A(CP) for B+-\u3ephi K+

We present the first evidence of charmless decays of the B-s(0) meson, the decay B-s(0)-\u3ephi phi, and a measurement of the branching ratio BR(B-s(0)-\u3ephi phi) using 180 pb(-1) of data collected by the CDF II experiment at the Fermilab Tevatron collider. In addition, the BR and direct CP asymmetry for the B+-\u3ephi K+ decay are measured. We obtain BR(B-s(0)-\u3ephi phi)=[14(-5)(+6)(stat)+/- 6(syst)]x10(-6), BR(B+-\u3ephi K+)=[7.6 +/- 1.3(stat)+/- 0.6(syst)]x10(-6), and A(CP)(B+-\u3ephi K+)=-0.07 +/- 0.17(stat)(-0.02)(+0.03)(syst). Both decays are governed in the standard model by second order (penguin) b -\u3e s(s) over bar s amplitudes

Evidence for the exclusive decay B-c(+/-)-\u3e J/psi pi(+/-) and measurement of the mass of the B-c(+/-) meson

We report the first evidence for a fully reconstructed decay mode of the B-c(+/-) meson in the channel B-c(+/-)-\u3e J/psi pi(+/-), with J/psi -\u3emu(+)mu(-). The analysis is based on an integrated luminosity of 360 pb(-1) in p (p) over bar collisions at 1.96 TeV center of mass energy collected by the Collider Detector at Fermilab. We observe 14.6 +/- 4.6 signal events with a background of 7.1 +/- 0.9 events, and a fit to the J/psi pi(+/-) mass spectrum yields a B-c(+/-) mass of 6285.7 +/- 5.3(stat)+/- 1.2(syst) MeV/c(2). The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%

Measurement of bottom-quark hadron masses in exclusive J/psi decays with the CDF detector

We measure the masses of b hadrons in exclusively reconstructed final states containing a J/psi ->mu(-)mu(+) decay using 220 pb(-1) of data collected by the CDF II experiment. We find: m(B(+))=5279.10 +/- 0.41((stat.))+/- 0.36((sys.)) MeV/c(2), m(B(0))=5279.63 +/- 0.53((stat.))+/- 0.33((sys.)) MeV/c(2), m(B(s)(0))=5366.01 +/- 0.73((stat.))+/- 0.33((sys.)) MeV/c(2), m(Lambda(0)(b))=5619.7 +/- 1.2((stat.))+/- 1.2((sys.)) MeV/c(2). m(B(+))-m(B(0))=-0.53 +/- 0.67((stat.))+/- 0.14((sys.)) MeV/c(2), m(B(s)(0))-m(B(0))=86.38 +/- 0.90((stat.))+/- 0.06((sys.)) MeV/c(2), m(Lambda(0)(b))-m(B(0))=339.2 +/- 1.4((stat.))+/- 0.1((sys.)) MeV/c(2). The measurements of the B(s)(0), Lambda(0)(b) mass, m(B(s)(0))-m(B(0)) and m(Lambda(0)(b))-m(B(0)) mass difference are of better precision than the current world averages