Measurement of the $b$-quark production cross-section in 7 and 13 TeV $pp$ collisions

Abstract

Measurements of the cross-section for producing \bquark quarks in the reaction $pp\to b\bar{b}X$ are reported in 7 and 13 TeV collisions at the LHC as a function of the pseudorapidity $\hat{I}\cdot$ in the range $2<\hat{I}\cdot <5$ covered by the acceptance of the LHCb experiment. The measurements are done using semileptonic decays of $b$-flavored hadrons decaying into a ground-state charmed hadron in association with a muon. The cross-sections in the covered $\hat{I}\cdot$ range are $72.0\pm 0.3\pm 6.8\hat{I}¼$b and $144\pm 1\pm 21\hat{I}¼$b for 7 and 13 TeV. The ratio is $2.00\pm 0.02\pm 0.26$, where the quoted uncertainties are statistical and systematic, respectively. The agreement with theoretical expectation is good at 7 TeV, but differs somewhat at 13 TeV. The measured ratio of cross-sections is larger at lower $\hat{I}\cdot$ than the model prediction.

This version incorporates the Errata and presents only the updated measurements. Erratum added on Sept. 1, 2017. Please use for 13 TeV cross-sections and cross-section ratios. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-031.html