First Measurement of the Ratio of Branching Fractions B(Lambdab to Lambdac mu nu)/B(Lambdab to Lambdac pi)
Abstract
The analysis uses data from an integrated luminosity of approximately 172 pb-1 of ppbar collisions at sqrt(s)=1.96 TeV, collected with the CDF II detector at the Fermilab Tevatron. The Lambdab and B0 relative branching fractions are measured to be: B(Lambdab to Lambdac+ mu nu)/B(Lambdab to Lambdac+ pi) = 16.6 +- 3.0 (stat) +- 1.0 (syst) +2.6 -3.4 (PDG) +- 0.3 (EBR), B(B0 to D+ mu nu)/B(B0 to D+ pi) = 9.9 +- 1.0 (stat) +- 0.6 (syst) +- 0.4 (PDG) +- 0.5 (EBR), B(B0 to D*+ mu nu)/B(B0 to D*+ pi) = 16.5 +- 2.3 (stat) +- 0.6 (syst) +- 0.5 (PDG) +- 0.8 (EBR) This article also presents measurements of the branching fractions of four new Lambdab semileptonic decays: Lambdab to Lambdac(2595)+ mu nu, Lambdab to Lambdac(2625)+ mu nu, Lambdab to Sigmac(2455)0 pi mu nu, Lambdab to Sigmac(2455)++ pi mu nu, relative to the branching fraction of the Lambdab to Lambdac mu nu decay. Finally, the transverse-momentum distribution of Lambdab baryons produced in p-pbar collisions is measured and found to be significantly different from that of B0 mesons.