B->V gamma Beyond QCD Factorisation

Ball, Patricia; Jones, Gareth W.; Zwicky, Roman

B->V gamma Beyond QCD Factorisation

Authors

Ball, Patricia

Jones, Gareth W.

Zwicky, Roman

Description

We calculate the main observables in $B_{u,d}\to (ρ,ω,K^*)γ$ and $B_s\to (\bar K^*,ϕ)γ$ decays, i.e. branching ratios and CP and isospin asymmetries. We include QCD factorisation results and also the dominant contributions beyond QCD factorisation, namely long-distance photon emission and soft-gluon emission from quark loops. All contributions beyond QCD factorisation are estimated from light-cone sum rules. We devise in particular a method for calculating soft-gluon emission, building on earlier ideas developed for analogous contributions in non-leptonic decays. Our results are relevant for new-physics searches at the $B$ factories, the LHC and a future super-flavour factory. Using current experimental data, we also extract $|V_{td}/V_{ts}|$ and the angle $γ$ of the unitarity triangle. We give detailed tables of theoretical uncertainties of the relevant quantities which facilitates future determinations of these CKM parameters from updated experimental results.
49 pages, version to appear in PRD