1206.4977 (Damir Becirevic et al.)

$\bar B\to Dτ\bar ν_τ$ vs. $\bar B\to Dμ\bar ν_μ$    [PDF]

Damir Becirevic, Nejc Kosnik, Andrey Tayduganov

Recent experimental results for the ratio of the branching fractions of $\bar B\to D^{(*)}\tau\bar \nu_\tau$ and $\bar B\to D^{(*)}\mu\bar \nu_\mu$ decays came as a surprise and lead to a discussion of possibility to constraining New Physics through these modes. Here we focus on ${\cal B}(\bar B\to D\tau\bar \nu_\tau)/{\cal B}(\bar B\to D\mu\bar \nu_\mu)$ and argue that the result is consistent with the Standard Model within $2\sigma$, and that the test of compatibility of this ratio with the Standard Model can be done experimentally with a minimal theory input.

View original: http://arxiv.org/abs/1206.4977