b-> s gamma and b-> d gamma (B factories)

Understand

The photon spectrum in B->X_{s,d} \gamma decay, where X_s(d) is any strange (non-strange) hadronic state, is studied using data samples of $e^+e^- \rightarrow \Upsilon(4S) \to B B-bar decays collected by the Babar and Belle experiments.

• Here I present the latest measurements of the branching fraction and spectral mo ments from B -> X_s gamma$ decays by Belle and the direct CP asymmetry of B->X_{s+d} gamma measured at Babar.
• The determination of |V_{td}/V_{ts}|^2$ i also presented.