|V_td/V_ts| from B-> V gamma
Abstract
The dominant theoretical uncertainty in extracting |V_td/V_ts| from the ratio of branching ratios R=B(B->(rho,omega)gamma)/B(B->K* gamma) is given by the ratio of form factors xi=T_1^{B->K*}(0)/T_1^{B->rho}(0). We re-examine xi in the framework of QCD sum rules on the light-cone, taking into account hitherto neglected SU(3)-breaking effects. We find xi=1.17 \pm 0.09. Using QCD factorisation for the branching ratios, and the current experimental average for R quoted by HFAG, this translates into |V_td/V_ts|^HFAG_{B->V gamma} = 0.192 \pm 0.014(th) \pm 0.016(exp). This result agrees, within errors, with that obtained from the Standard Model unitarity triangle, |V_td/V_ts|_SM = 0.216 \pm 0.029, based on tree-level-only processes, and with |V_td/V_ts|_{Delta m} = 0.2060^{+0.0081}_{-0.0060}(th) \pm 0.0007(exp), from the CDF measurement of B_s oscillations.
Cite
@article{arxiv.hep-ph/0603232,
title = {|V_td/V_ts| from B-> V gamma},
author = {Patricia Ball and Roman Zwicky},
journal= {arXiv preprint arXiv:hep-ph/0603232},
year = {2011}
}
Comments
23 pages; new BaBar results on B->(rho/omega)gamma included