Studies of B_s Production and Semileptonic Decay, and of Antideuteron Production in Upsilon Decay and Quark Fragmentation at BaBar

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Hamilton, Brian Keith
Jawahery, Abolhassan
I present a measurement of the inclusive semileptonic branching fraction of the B<sub>s</sub> meson and B<sub>s</sub> production rates relative to all B mesons using a data set collected with the BaBar detector at the PEP-II asymmetric energy electron-positron collider operating at center-of-mass energies above the Upsilon(4S) resonance. The quantities are extracted simultaneously using inclusive yields of phi mesons and phi mesons in coincidence with a high momentum lepton. The B<sub>s</sub> semileptonic branching fraction is found to be B(B<sub>s<\sub> &rarr; l &nu; X) = (9.5<sup>+2.5</sup><sub>-2.0</sub><sup>+1.1</sup><sub>-1.9</sub>)%, where the first uncertainty is statistical and the second is systematic. Additionally, I present measurements of antideuteron production using the BaBar data collected at collision center-of-mass energies corresponding to the masses of the Upsilon(2S), Upsilon(3S), and Upsilon(4S) resonances. Measurements of specific ionization for charged tracks in the \babar\ detector are used to obtain the antideuteron production rate in decays of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) resonances as well as in continuum e<sup>+</sub>e<sup>-</sup> annihilation to hadrons. The total rates observed in the data are B(Upsilon(2S) &rarr; dbar X) = (2.62 &plusmn; 0.10<sup>+0.31</sup><sub>-0.28</sub>)&times; 10<sup>-5</sup>, B(Upsilon(1S) &rarr; dbar X) = (2.85 &plusmn; 0.47<sup>+0.21</sup><sub>-0.29</sub>)&times; 10<sup>-5</sup>, B(Upsilon(3S) &rarr; dbar X) = (2.45 &plusmn; 0.14<sup>+0.27</sup><sub>-0.24</sub>)&times; 10<sup>-5</sup>, and the cross section for antideuteron production in continuum e<sup>+</sub>e<sup>-</sup> annihilation is found to be &sigma;(e<sup>+</sub>e<sup>-</sup> (10.58 GeV) &rarr; dbar X) = (10.49 &plusmn; 0.33<sup>+1.28</sup><sub>-1.14</sub>) fb. No significant production in Upsilon(4S) decays is observed.