David Bacher

Abstract:

A bstract This paper reports the observation of the decays $$ {B}_{(s)}^0 $$ B s 0 → D s 1 (2536) ∓ K ± using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb − 1 . The branching fractions of these decays are measured relative to the normalisation channel B 0 → $$ \overline{D} $$ D ¯ 0 K + K − . The D s 1 (2536) − meson is reconstructed in the $$ \overline{D} $$ D ¯ * (2007) 0 K − decay channel and the products of branching fractions are measured to be $$ {\displaystyle \begin{array}{c}\mathcal{B}\left({B}_s^0\to {D}_{s1}{(2536)}^{\mp }{K}^{\pm}\right)\times \mathcal{B}\left({D}_{s1}{(2536)}^{-}\to {\overline{D}}^{\ast }{(2007)}^0{K}^{-}\right)\\ {}=\left(2.49\pm 0.11\pm 0.12\pm 0.25\pm 0.06\right)\times {10}^{-5},\\ {}\mathcal{B}\left({B}^0\to {D}_{s1}{(2536)}^{\mp }{K}^{\pm}\right)\times \mathcal{B}\left({D}_{s1}{(2536)}^{-}\to {\overline{D}}^{\ast }{(2007)}^0{K}^{-}\right)\\ {}=\left(0.510\pm 0.021\pm 0.036\pm 0.050\right)\times {10}^{-5}.\end{array}} $$ B B s 0 → D s 1 2536 ∓ K ± × B D s 1 2536 − → D ¯ ∗ 2007 0 K − = 2.49 ± 0.11 ± 0.12 ± 0.25 ± 0.06 × 10 − 5 , B B 0 → D s 1 2536 ∓ K ± × B D s 1 2536 − → D ¯ ∗ 2007 0 K − .

Abstract:

A limit on the branching fraction for the decay Bo→γγ was presented using data collected at the γ(4S) resonance at the PEP-II asymmetric energy collider. The energy resolution was measured with a radioactive source at low energy and with electrons from Bhabha scattering at high energy. The energy deposits were reconstructed by grouping adjacent crystals with energy deposits greater than 1 MeV into clusters.