We have observed bottom-charm mesons via the decay mode B-c(+/-) --> J/psi l(+/-)v in 1.8 TeV p (p) over bar collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi l mass distribution yielded 20.4(-5.5)(+6.2) events from B-c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B-c(+) mass to be 6.40 +/- 0.39(stat) +/- 0.13(syst) GeV/c(2) and the B-c(+) lifetime to be 0.46(-0.16)(+0.18)(stat) +/- 0.03(syst) ps. Our measured yield (production cross section times branching ratio) for B-c(+) --> J/psi l(+)v relative to that for B+ --> J/psi K+ is 0.132(-0.037)(+0.041)(stat) +/- 0.031 (syst)(-0.020)(+0.032)(lifetime).
Observation of the B-c meson in p(p)over-bar collisions at root s=1.8 TeV
BISELLO, DARIO;BUSETTO, GIOVANNI;LUCCHESI, DONATELLA;MARIOTTI, MOSE';MENGUZZATO, MATTEO;
1998
Abstract
We have observed bottom-charm mesons via the decay mode B-c(+/-) --> J/psi l(+/-)v in 1.8 TeV p (p) over bar collisions using the CDF detector at the Fermilab Tevatron. A fit of background and signal contributions to the J/psi l mass distribution yielded 20.4(-5.5)(+6.2) events from B-c mesons. A fit to the same distribution with background alone was rejected at the level of 4.8 standard deviations. We measured the B-c(+) mass to be 6.40 +/- 0.39(stat) +/- 0.13(syst) GeV/c(2) and the B-c(+) lifetime to be 0.46(-0.16)(+0.18)(stat) +/- 0.03(syst) ps. Our measured yield (production cross section times branching ratio) for B-c(+) --> J/psi l(+)v relative to that for B+ --> J/psi K+ is 0.132(-0.037)(+0.041)(stat) +/- 0.031 (syst)(-0.020)(+0.032)(lifetime).Pubblicazioni consigliate
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