Measurement of b hadron production fractions in 7 TeV pp collisions
Abstract
Measurements of b hadron production ratios in proton-proton collisions at a centre-of-mass energy of 7 TeV with an integrated luminosity of 3 pb-1 are presented. We study the ratios of strange B meson to light B meson production fs/(fu+fd) and b0 baryon to light B meson production f_b/(fu+fd) as a function of the charmed hadron-muon pair transverse momentum pT and the b hadron pseudorapidity η, for pT between 0 and 14 GeV and η between 2 and 5. We find that fs/(fu+fd) is consistent with being independent of p T and η, and we determine fs/(fu+fd) = 0.134 0.004 +0.011-0.010, where the first error is statistical and the second systematic. The corresponding ratio f_b/(fu+fd) is found to be dependent upon the transverse momentum of the charmed hadron-muon pair, f_b/(fu+fd)=(0.404 0.017 (stat) 0.027 (syst) 0.105 (Br))×[1 -(0.031 0.004 (stat) 0.003 (syst))× pT(GeV)], where Br reflects an absolute scale uncertainty due to the poorly known branching fraction Br(c+ pK-π+). We extract the ratio of strange B meson to light neutral B meson production fs/fd by averaging the result reported here with two previous measurements derived from the relative abundances of Bs DS+ π - to B0 D+K- and B0 D+π-. We obtain fs/fd=0.267+0.021-0.020$.