Measurement of Ratios of Fragmentation Fractions for Bottom Hadrons in p anti-p Collisions at s**(1/2) = 1.96-TeV

This paper describes the first measurement of b-quark fragmentation fractions into bottom hadrons in Run II of the Tevatron Collider at Fermilab. The result is based on a 360 pb{sup -1} sample of data collected with the CDF II detector in pp collisions at {radical}(s)=1.96 TeV. Semileptonic decays of B{sup 0}, B{sup -}, and B{sub s}{sup 0} mesons, as well as {lambda}{sub b}{sup 0} baryons, are reconstructed. For an effective bottom hadron p{sub T} threshold of 7 GeV/c, the fragmentation fractions are measured to be f{sub u}/f{sub d}=1.054{+-}0.018(stat){sub -0.045}{sup +0.025}(sys){+-}0.058(B), f{sub s}/(f{sub u}+f{sub d})=0.160{+-}0.005(stat){sub -0.010}{sup +0.011}(sys){sub -0.034}{sup +0.057}(B), and f{sub {lambda}{sub b}}/(f{sub u}+f{sub d})=0.281{+-}0.012(stat){sub -0.056}{sup +0.058}(sys){sub -0.087}{sup +0.128}(B), where the uncertainty B is due to uncertainties on measured branching ratios. The value of f{sub s}/(f{sub u}+f{sub d}) agrees within one standard deviation with previous CDF measurements and the world average of this quantity, which is dominated by LEP measurements. However, the ratio f{sub {lambda}{sub b}}/(f{sub u}+f{sub d}) is approximately twice the value previously measured at LEP. The approximately 2{sigma} discrepancy is examined in terms of kinematic differences between the two production environments.