PHYSICAL REVIEW D 85, 032008 (2012) Measurement of b hadron production fractions in 7 TeV pp collisions
R. Aaji et al.* (The LHCb Collaboration) (Received 9 November 2011; published 24 February 2012) Measurements of b hadron production ratios in proton-proton collisions at a center-of-mass energy of 7 TeV with an integrated luminosity of 3pb 1 are presented. We study the ratios of strange B meson to B f =ðf þ f Þ 0 B f =ðf þ f Þ light meson production s u d and b baryon to light meson production b u d as a function of the charmed hadron-muon pair transverse momentum pT and the b hadron pseudorapidity , for pT between 0 and 14 GeV and between 2 and 5. We find that fs=ðfu þ fdÞ is consistent with being þ0:011 independent of pT and , and we determine fs=ðfu þ fdÞ¼0:134 0:004 0:010, where the first error is f =ðf þ f Þ statistical and the second systematic. The corresponding ratio b u d is found to be dependent f =ðf þf Þ¼ð0:404 0:017ðstatÞ upon the transverse momentum of the charmed hadron-muon pair, b u d 0:027ðsystÞ 0:105ðBrÞÞ ½1 ð0:031 0:004ðstatÞ 0:003ðsystÞÞ pTðGeVÞ , where Br reflects an abso- þ þ lute scale uncertainty due to the poorly known branching fraction Bð c ! pK Þ. We extract the ratio of strange B meson to light neutral B meson production fs=fd by averaging the result reported here with 0 þ 0 þ two previous measurements derived from the relative abundances of Bs ! Ds to B ! D K and 0 þ þ0:021 B ! D . We obtain fs=fd ¼ 0:267 0:020.
DOI: 10.1103/PhysRevD.85.032008 PACS numbers: 13.25.Hw, 14.20.Mr