# 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 $f_s/(f_u+f_d)$ and $Lambda_b^0$ baryon to light $B$ meson production $f_{Lambda_b}/(f_u+f_d)$ as a function of the charmed hadron-muon pair transverse momentum $p_T$ and the $b$ hadron pseudorapidity $eta$, for $p_T$ between 0 and 14 GeV and $eta$ between 2 and 5. We find that $f_s/(f_u+f_d)$ is consistent with being independent of $p_{rm T}$ and $eta$, and we determine $f_s/(f_u+f_d)$ = 0.134$pm$ 0.004 $^{+0.011}_{-0.010}$, where the first error is statistical and the second systematic. The corresponding ratio $f_{Lambda_b}/(f_u+f_d)$ is found to be dependent upon the transverse momentum of the charmed hadron-muon pair, $f_{Lambda_b}/(f_u+f_d)=(0.404pm 0.017 (stat) pm 0.027 (syst) pm 0.105 (Br))times[1 -(0.031 pm 0.004 (stat) pm 0.003 (syst))times p_T(GeV)]$, where Br reflects an absolute scale uncertainty due to the poorly known branching fraction Br(Lambda_c^+ to pK^-pi^+)$. We extract the ratio of strange$B$meson to light neutral$B$meson production$f_s/f_d$by averaging the result reported here with two previous measurements derived from the relative abundances of$bar{B}_s to D_S^+ pi ^-$to$bar{B}^0 to D^+K^-$and$bar{B}^0 to D^+pi^-$. We obtain$f_s/f_d=0.267^{+0.021}_{-0.020}\$.
Document type :
Journal articles

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Submitted on : Monday, November 14, 2011 - 5:03:57 PM
Last modification on : Saturday, January 15, 2022 - 3:08:11 PM

### Citation

R. Aaij, C. Abellan Beteta, B. Adeva, M. Adinolfi, C. Adrover, et al.. Measurement of b hadron production fractions in 7 TeV pp collisions. Physical Review D, American Physical Society, 2012, 85, pp.032008. ⟨10.1103/PhysRevD.85.032008⟩. ⟨in2p3-00641064⟩

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