Abstract
Abstract The relative production rate of $ B_s^0 $ and B 0 mesons is determined with the hadronic decays $ B_s^0\to D_s^{-}{\pi^{+}} $ and B 0 → D − K +. The measurement uses data corresponding to 1.0 fb−1 of pp collisions at a centre-of-mass energy of $ \sqrt{s}=7 $ TeV recorded in the forward region with the LHCb experiment. The ratio of production rates, f s /f d , is measured to be 0.238 ± 0.004 ± 0.015 ± 0.021, where the first uncertainty is statistical, the second systematic, and the third theoretical. This is combined with a previous LHCb measurement to obtain f s /f d = 0.256 ± 0.020. The dependence of f s /f d on the transverse momentum and pseudorapidity of the B meson is determined using the decays $ B_s^0\to D_s^{-}{\pi^{+}} $ and B 0 → D −π+. There is evidence for a decrease with increasing transverse momentum, whereas the ratio remains constant as a function of pseudorapidity. In addition, the ratio of branching fractions of the decays B 0 → D − K + and B 0 → D −π+ is measured to be 0.0822 ± 0.0011 (stat) ± 0.0025 (syst).
Highlights
A centre-of-mass energy of s = 7 TeV recorded in the forward region with the LHCb experiment
The ratio of fragmentation fractions can depend on the centre-of-mass energy, as well as on the kinematics of the B(0s) meson, as was studied previously at LHCb with partially reconstructed B decays [4]
This is combined with the world average branching fraction B B0 → D−π+ = (26.8 ± 1.3) × 10−4 [2], to give
Summary
The LHCb detector [12] is a single-arm forward spectrometer covering the pseudorapidity range 2 < η < 5, designed for the study of particles containing b or c quarks. 0.4% at 5 GeV/c to 0.6% at 100 GeV/c, and impact parameter resolution of 20 μm for tracks with high transverse momentum. The events used in this analysis are selected at the hardware stage by requiring a cluster in the calorimeters with transverse energy larger than 3.6 GeV. The software stage requires a two-, three- or four-track secondary vertex with a high sum of the pT of the tracks and a significant displacement from the primary pp interaction vertices (PVs). Decays of hadronic particles are described by EvtGen [16], whilst final state radiation is generated using Photos [17]. The interaction of the generated particles with the detector and its response are implemented using the Geant toolkit [18, 19] as described in ref. The interaction of the generated particles with the detector and its response are implemented using the Geant toolkit [18, 19] as described in ref. [20]
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