Measurement of Inclusive Radiative B-meson Decays with a Photon Energy Threshold of 1.7 GeV

TL;DR

This paper reports a precise measurement of the inclusive radiative B-meson decay rate with photon energy thresholds between 1.7 and 2.0 GeV, providing important data for testing the Standard Model and constraining new physics.

Contribution

It presents the first measurement of the partial branching fraction and photon energy spectrum of B to X_s gamma decays at multiple energy thresholds using a large data sample.

Findings

Partial branching fraction at 1.7 GeV threshold: (3.45 +/- 0.15 +/- 0.40) x 10^-4

Photon energy spectrum mean and variance measured at various thresholds

Results improve constraints on new physics models involving flavor-changing neutral currents

Abstract

Using 605/fb of data collected at the Upsilon(4S) resonance we present a measurement of the inclusive radiative B-meson decay channel, B to X_s gamma. For the lower photon energy thresholds of 1.7, 1.8, 1.9 and 2.0GeV, as defined in the rest frame of the B-meson, we measure the partial branching fraction and the mean and variance of the photon energy spectrum. At the 1.7GeV threshold we obtain the partial branching fraction BF(B to X_s gamma) = (3.45 +/- 0.15 +/- 0.40) x 10^-4, where the errors are statistical and systematic.