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

Evidence for the exclusive decay Bc±→J/ψπ± and measurement of the mass of the Bc± meson

We report the first evidence for a fully reconstructed decay mode of the Bc± meson in the channel Bc±→J/ψπ±, with J/ψ→μ+μ-. The analysis is based on an integrated luminosity of 360pb-1 in pp̄ 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/ψπ± mass spectrum yields a Bc± mass of 6285.7±5.3(stat)±1. 2(syst)MeV/c2. The probability of a peak of this magnitude occurring by random fluctuation in the search region is estimated as 0.012%. © 2006 The American Physical Society

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