QCD Corrections to Radiative Upsilon Decays

TL;DR

This paper calculates next-to-leading order QCD corrections to the photon energy spectrum in radiative Upsilon decays, improving theoretical predictions and aiding precise determination of the strong coupling constant.

Contribution

It provides the first NLO perturbative QCD calculation of the photon spectrum in radiative Upsilon decays, refining previous models and reducing discrepancies with experimental data.

Findings

Higher-order corrections significantly alter the spectrum shape at large energies.

NLO calculations improve agreement with experimental data.

The results enable more accurate extraction of the strong coupling constant.

Abstract

We have calculated the next-to-leading order perturbative QCD corrections to the photon energy spectrum in radiative Upsilon decays. The higher-order corrections significantly modify the shape of the spectrum, in particular at large photon energies, and thereby reduce the discrepancy between experimental data and previous leading-order predictions. The next-to-leading order calculation of the photon energy spectrum allows a more reliable determination of the strong coupling constant from radiative Upsilon decays by restricting the analysis to the region of the energy spectrum that can be described by NLO perturbation theory.