Color-octet effects in radiative {Upsilon} decays

Journal Article · Thu Apr 01 04:00:00 EST 1999 · Physical Review, D

DOI:https://doi.org/10.1103/PhysRevD.59.074006· OSTI ID:322025

Maltoni, F ^[1]; Petrelli, A ^[2]

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1. CERN, TH Division, Geneva (Switzerland)
2. Argonne National Laboratory, HEP Division, Argonne, Illinois 60439 (United States)

We investigate the effects of color-octet contributions to the radiative {Upsilon} decay within the Bodwin, Braaten, and Lepage nonrelativistic QCD (NRQCD) framework. We compute the short-distance coefficients at next-to-leading order (NLO) in {alpha}{sub s} for the most relevant color-octet intermediate states and consider photons coming both from the coupling to hard processes ({open_quotes}direct{close_quotes}) and by collinear emission from light quarks ({open_quotes}fragmentation{close_quotes}). An estimate for the nonperturbative matrix elements which enter in the final result is then obtained. By comparing the NRQCD prediction at NLO for total decay rates with the experimental data, it is found that the nonperturbative parameters must be smaller than expected from the naive scaling rules of NRQCD. Nevertheless, color-octet contributions to the shape of the photon spectrum turn out to be significant. {copyright} {ital 1999} {ital The American Physical Society}

• OSTI ID: 322025
• Journal Information: Physical Review, D, Journal Name: Physical Review, D Journal Issue: 7 Vol. 59; ISSN 0556-2821; ISSN PRVDAQ
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
COLOR MODEL
MATRIX ELEMENTS
MESONS
PARTICLE DECAY
QUANTUM CHROMODYNAMICS
RADIATIVE DECAY
SCALING LAWS