The Resummed Photon Spectrum in Radiative Upsilon Decays

TL;DR

This work presents a theoretical prediction for the photon spectrum in radiative upsilon decay including the effects of resumming the end point region, E(gamma)-->M(upsilon)/2.

Abstract

We present a theoretical prediction for the photon spectrum in radiative Upsilon decay including the effects of resumming the endpoint region, E_γ-> M_Υ/2. Our approach is based on NRQCD and the soft collinear effective theory. We find that our results give much better agreement with data than the leading order NRQCD prediction.

Figures (3)

• Figure 1: Feynman diagram for the leading order jet function. Collinear gluons are represented by a spring with a line.
• Figure 2: Diagrams needed to calculate the CS counterterm.
• Figure 3: The inclusive photon spectrum, compared with data Nemati:1996xy. The theory predictions are described in the text.