Color-octet effects in radiative Υ decays
نویسندگان
چکیده
منابع مشابه
Octet contributions in radiative Υ decays
The standard Non-Relativistic QCD (NRQCD) factorization [1] (operator product expansion) breaks down at the end-point region of the photon spectrum in semi-inclusive radiative decays of heavy quarkonium; this is due to the fact that collinear degrees of freedom, that are relevant in this kinematic situation, are not included in NRQCD. A proper effective field theory treatment of the end-point r...
متن کاملResumming the color-octet contribution to radiative Υ decay
At the upper endpoint of the photon energy spectrum in Υ → Xγ, the standard NRQCD power counting breaks down and the OPE gives rise to color-octet structure functions. Furthermore, in this kinematic regime large Sudakov logarithms appear in the octet Wilson coefficients. The endpoint spectrum can be treated consistently within the framework of a recently developed effective field theory of coll...
متن کاملQCD Corrections to Radiative Υ Decays
We have calculated the next-to-leading order perturbative QCD corrections to the photon energy spectrum in radiative Υ 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 ...
متن کاملColor - Octet J / ψ Production in the Υ Decay
The direct production rate of ψ in the Υ decay is shown to be dominated by the process Υ → ggg followed by g → ψ via the color-octet mechanism proposed recently to explain the anomalous prompt charmonium production at the Tevatron. We show that this plausibly dominant process has a branching ratio compatible with the experimental data. Further experimental study in this channel is important to ...
متن کاملΥ decay into charmonium and the color octet mechanism
A factorization theorem for P -wave quarkonium production, recently derived by Bodwin, Braaten, Yuan and Lepage, is applied to Υ → χcJ +X, where χcJ labels the PJ charmonium states. The widths for χcJ production through color-singlet P -wave and color-octet S-wave cc̄ subprocesses are computed each to leading order in αs. Experimental data on Υ → J/ψ+X is used to obtain an upper bound on a nonpe...
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ژورنال
عنوان ژورنال: Physical Review D
سال: 1999
ISSN: 0556-2821,1089-4918
DOI: 10.1103/physrevd.59.074006