Alexander L. Kagan

QCD anatomy of \(B\to X_s\gamma\) decays

Abstract. We present an updated next-to-leading order analysis of the

General Minimal Flavor Violation

B\to X_s\gamma

New physics and CP violation in singly Cabibbo suppressed D decays

branching ratio and photon spectrum, including consistently the effects of Fermi motion in the heavy-quark expansion. For the Standard Model, we obtain

750 GeV diphoton excess

{\rm B}(B\to X_s\gamma)=(2.57\pm 0.26_{-0.36}^{+0.31})\times 10^{-4}

Size of direct CP violation in singly Cabibbo-suppressed D decays

for the integral over the high-energy part of the photon spectrum with

Polarization in B→VV decays

E_\gamma^{\rm lab}> 2.2

Isospin breaking in

GeV, where the first error reflects the uncertainty in the input parameters, and the second one the uncertainty in the calculation of Fermi motion. This prediction agrees with the CLEO measurement of the same quantity within one standard deviation. From a reanalysis of the CLEO data, we obtain for the total branching ratio

B \to K^* \gamma

{\rm B}(B\to X_s\gamma)=(2.62\pm 0.60_{\rm exp}\,\mbox{}^{+0.37}_{-0.30\,{\rm th}})\times 10^{-4}

decays

using the measured rate above 2.2 GeV, and

Forward-backward asymmetry in tt production from flavor symmetries.

(2.66\pm 0.56_{\rm exp}\,\mbox{}^{+0.43}_{-0.48\,{\rm th}})\times 10^{-4}