Measurement of the production fraction times branching fraction f(b -} Lambda(b)) . B(Lambda(b) -} J/psi Lambda)
2011
Abstract
The Lambda(b)(udb) baryon is observed in the decay Lambda(b) -} J/psi Lambda using 6.1fb(-1) of p (p) over bar collisions collected with the D0 detector at sqrt(s) = 1/96 TeV. The production fraction multiplied by the branching fraction for this decay relative to that for the decay B(0) -} J/psi K(s)(0) is measured to be 0.345 +/- 0.034(stat) +/- 0.033(syst) +/- 0.003(PDG).
Using the world average value of f(b -} B(0)). B(B(0) -} J/psi K(s)(0) = (1.74 +/- 0.08) x 10(-5), we obtain f(b -} Lambda(b)).
B(Lambda(b) -} J/psi Lambda) = (6.01 +/- 0.60(stat) +/- 0.58(syst) +/- 0.28(PDG)) x 10(-5). This measurement represents an improvement in precision by about a factor of 3 with respect to the current world average.