Measurements of the cross-section for producing bquark quarks in the reaction $ppto bbar{b} X$ are reported in 7 and 13 TeV collisions at the LHC as a function of the pseudorapidity $eta$ in the range $2<eta<5$ 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 $eta$ range are $72.0pm 0.3pm6.8~mu$b and $144pm 1pm 21~mu$b for 7 and 13 TeV. The ratio is $2.00pm0.02pm0.26$, 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 $eta$ than the model prediction.
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