Clark, Brian LeeFranklin, MelissaHuth, JohnIppolito, ValerioLazovich, TomoLopez Mateos, DavidMercurio, KevinMorii, MasahiroSpearman, WilliamSun, SiyuanTolley, EmmaYen, AndyZambito, Stefano2017-12-052015ATLAS Collaboration. 2015. “Determination of the ratio of b-quark fragmentation fractions fs/fd in pp collisions at s√=7 TeV with the ATLAS detector.” Physical Review Letters 115 (26) (December 30). doi:10.1103/physrevlett.115.262001.0031-9007http://nrs.harvard.edu/urn-3:HUL.InstRepos:34469825With 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.en-USJournal Article2017-12-0510.1103/PhysRevLett.115.262001