Photon polarization in B → Xγ in the standard model

Benjamín Grinstein, Yuval Grossman, Zoltan Ligeti, Dan Pirjol

Research output: Contribution to journalArticlepeer-review

100 Scopus citations


The standard model prediction for the B̄0 → X s,dγ decay amplitude with a right-handed photon is believed to be tiny, suppressed by ms,d/mb, compared to the amplitude with a left-handed photon. We show that this suppression is fictitious: In inclusive decays, the ratio of these two amplitudes is only suppressed by g s/(4π), and in exclusive decays by ΔQCD/m b. The suppression is not stronger in B̄0 → Xdγ decays than it is in B̄0 → X sγ. We estimate that the time dependent CP asymmetries in B → K*γ, ργ, Ksπ0γ, and π+π-γ are of order 0.1 and that thev have significant uncertainties.

Original languageEnglish
Article number011504
Pages (from-to)011504-1-011504-5
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number1
StatePublished - Jan 2005
Externally publishedYes


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