First measurement of the ratio of branching fractions B(Lambda(0)(b) -> Lambda(+)(c) mu(-) (nu)over-bar(mu))/B(Lambda(0)(b) -> Lambda(+)(c) pi(-))

Abstract

This article presents the first measurement of the ratio of branching fractions B(Lambda(0)(b) -> Lambda(+)(c) mu(-) (nu) over bar (mu))/B(Lambda(0)(b) -> Lambda(+)(c) pi(-)). Measurements in two control samples using the same technique B((B) over bar (0) -> D+ mu(-) (nu) over bar (mu))/B((B) over bar (0) -> D+ pi(-)) and B((B) over bar (0) -> D*(2010)(+) mu(-) (nu) over bar (mu))/B((B) over bar (0) -> D*(2010)(+) pi(-)) are also reported. The analysis uses data from an integrated luminosity of approximately 172 pb(-1) of p (p) over bar collisions at root s = 1: 96 TeV, collected with the CDF II detector at the Fermilab Tevatron. The relative branching fractions are measured to be B(Lambda(0)(b) -> Lambda(+)(c) mu(-) (nu) over bar (mu))/B(Lambda(0)(b) -> Lambda(+)(c) pi(-)) = 16.6 +/- 3.0(stat) +/- 1.0(syst) (+2.6)(-3.4) (PDG) +/- 0.3(EBR), B((B) over bar (0) -> D+ mu(-) (nu) over bar (mu))/B((B) over bar (0) -> D+ pi(-)) = 9.9 +/- 1.0(stat) +/- 0.6(syst) +/- 0.4(PDG) +/- 0.5(EBR), and B((B) over bar (0)-> D*(2010)(+) mu(-) (nu) over bar (mu))/B((B) over bar (0) -> D*(2010)(+) pi(-)) = 16.5 +/- 2.3(stat) +/- 0.6(syst) +/- 0.5(PDG) +/- 0.8(EBR). The uncertainties are from statistics (stat), internal systematics (syst), world averages of measurements published by the Particle Data Group or subsidiary measurements in this analysis (PDG), and unmeasured branching fractions estimated from theory (EBR), respectively. This article also presents measurements of the branching fractions of four new Lambda(0)(b) semileptonic decays: Lambda(0)(b) -> Lambda(c)(2595)(+) mu(-) (nu) over bar (mu), Lambda(0)(b) -> Lambda(c)(2625)(+) mu(-) (nu) over bar (mu), Lambda(0)(b) -> Sigma(c)(2425)(0) pi(+) mu(-) (nu) over bar (mu) , and Lambda(0)(b) -> Sigma(c)(2455)(++) pi(-) mu(-) (nu) over bar (mu), relative to the branching fraction of the Lambda(0)(b) -> Lambda(+)(c) mu(-) (nu) over bar (mu) decay. Finally, the transverse-momentum distribution of Lambda(0)(b) baryons produced in p (p) over bar collisions is measured and found to be significantly different from that of (B) over bar (0) mesons, which results in a modification in the production crosssection ratio sigma(Lambda b0)/sigma((B) over bar0) with respect to the CDF I measurement.