Determination of the ratio of b-quark fragmentation fractions fs/fd in pp collisions at s√=7 TeV with the ATLAS detector

Abstract

With an integrated luminosity of 2.47 fb−1 recorded by the ATLAS experiment at the LHC, the exclusive decays B0s→J/ψϕ and B0d→J/ψK∗0 of B mesons produced in pp collisions at s√=7 TeV are used to determine the ratio of fragmentation fractions fs/fd. From the observed B0s→J/ψϕ and B0d→J/ψK∗0 yields, the quantity fsfd(B0s→J/ψϕ)(B0d→J/ψK∗0) is measured to be 0.199 ± 0.004(stat) ± 0.008(sys). Using a recent theory prediction for (B0s→J/ψϕ)(B0d→J/ψK∗0) yields fsfd= 0.240 ± 0.004(stat) ± 0.010(sys) ± 0.017(th). This result is based on a new approach that provides a significant improvement of the world average.