17-24 July 2013
KTH and Stockholm University Campus
Europe/Stockholm timezone

Semileptonic B and Bs decays at Belle

18 Jul 2013, 09:45
D1 (KTH Campus)


KTH Campus

Talk presentation Flavour Physics and Fundamental Symmetries Flavour Physics and fundamental symmetries


Aleksey Sibidanov (Budker Institute of Nuclear Physics (BINP))


We present measurements of exclusive and inclusive semileptonic $B_s$ decays using 121 $\rm{fb}^{-1}$ of data collected with the Belle detector near the $\Upsilon(5S)$ resonance. The inclusive branching fraction ${\cal B}(B_s \to X^- \ell^+ \nu_\ell)$ is measured in a sample enhanced in $B_s^{(*)0}\bar{B}_s^{(*)0}$ pair events by reconstructing a tag $D_s^+$ meson. The signal lepton $\ell^+ = e^+,\mu^+$ is required to be of the same-sign charge as the tag $D_s^+$ meson to ensure that both stem from different $B_s^0$ mesons. The branching fraction is extracted by comparing the ratio of measured $D_s^+$ and $D_s^+\ell^+$ yields to known production and branching fractions. The exclusive decays $B_s^0 \to D_s^{(*)-} \ell^+ \nu_\ell$ are studied in events where a lepton candidate $\ell^+$ is paired with a $D_s^-$ of the opposite-sign charge. We exploit the knowledge of the collision energy to identify signal decays based on the zero mass hypothesis for the unreconstructed neutrino.

Primary author

Prof. Youngjoon Kwon (Yonsei University)

Presentation Materials