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Measurement of $B$ meson production cross-sections in proton-proton collisions at $\sqrt{s}=$ 7 TeV

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Abstract

The production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV, using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36 fb-1. The B+, B0 and Bs0 mesons are reconstructed in the exclusive decays B+ -> J/psi K+, B0 -> J/psi K*0 and Bs0 -> J/psi phi, with J/psi -> mu+ mu-, K*0 -> K+ pi- and phi -> K+ K-. The differential cross-sections are measured as functions of B meson transverse momentum pT and rapidity y, in the range 0 < pT < 40 GeV/c and 2.0 < y < 4.5. The integrated cross-sections in the same pT and y ranges, including charge-conjugate states, are measured to be sigma(pp -> B+ + X) = 38.9 +- 0.3 (stat.) +- 2.5 (syst.) +- 1.3 (norm.) mub, sigma(pp -> B0 + X) = 38.1 +- 0.6 (stat.) +- 3.7 (syst.) +- 4.7 (norm.) mub, sigma(pp -> Bs0 + X) = 10.5 +- 0.2 (stat.) +- 0.8 (syst.) +- 1.0 (norm.) mub, where the third uncertainty arises from the pre-existing branching fraction measurements.

Figures and captions

Invariant mass distributions of the selected candidates for ({\it top left}) $ B^{\rm +}$ and ({\it top right}) $ B^{\rm 0}$ decays, both in the range $4.5< p_{\rm T}<5.0\; {\mathrm{\,GeV\!/}c} $, $3.0<y<3.5$, and ({\it bottom}) $ B^{\rm 0}_s$ decay in the range $4.0< p_{\rm T}<5.0\; {\mathrm{\,GeV\!/}c} $, $3.0<y<3.5$. The results of the fit to the model described in the text are superimposed. The Cabibbo-suppressed background is barely visible in the top left plot.

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Differential production cross-sections for ({\it top}) $ B^{\rm +}$ , ({\it middle}) $ B^{\rm 0}$ and ({\it bottom}) $ B^{\rm 0}_s$ \ mesons, as functions of $ p_{\rm T}$ \ for each $y$ interval.

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Differential production cross-sections for ({\it top}) $ B^{\rm +}$ , ({\it middle}) $ B^{\rm 0}$ and ({\it bottom}) $ B^{\rm 0}_s$ \ mesons, as functions of $ p_{\rm T}$ \ integrated over the whole $y$ range. The open circles with error bars are the measurements (not including uncertainties from normalisation channel branching fractions and luminosity) and the blue shaded areas are the uncertainties from the branching fractions. The red dashed lines are the upper and lower uncertainty limits of the FONLL computation [3].

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Differential production cross-sections for ({\it top}) $ B^{\rm +}$ , ({\it middle}) $ B^{\rm 0}$ and ({\it bottom}) $ B^{\rm 0}_s$ \ mesons, as functions of $y$ integrated over the whole $ p_{\rm T}$ range. The black open circles with error bars are the measurements (not including uncertainties from normalisation channel branching fractions and luminosity) and the blue shaded areas are the uncertainties from the branching fractions. The red dashed lines are the upper and lower uncertainty limits of the FONLL computation [3].

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Animated gif made out of all figures.

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Tables and captions

Relative systematic uncertainties (in %), given as single values or as ranges, when they depend on the ( $ p_{\rm T}$ , y) bin.

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Created on 09 December 2018.Citation count from INSPIRE on 09 December 2018.