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arXiv · hep-ph/0612081

B->V gamma Beyond QCD Factorisation

Patricia Ball·Gareth W. Jones·Roman Zwicky
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Abstract

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.

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Patricia Ball, Gareth W. Jones, Roman Zwicky. 2007-02-09. B->V gamma Beyond QCD Factorisation. https://doi.org/10.1103/physrevd.75.054004

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