منابع مشابه
Radiative Upsilon Decay at the Endpoint
The standard NRQCD power counting breaks down and the OPE gives rise to color-octet shape functions at the upper endpoint of the photon energy spectrum in radiative Υ decay. Also in this kinematic regime, large Sudakov logarithms appear in the octet Wilson coefficients, ruining the perturbative expansion. Using SCET, the octet shape functions arise naturally and the Sudakov logarithms can be su...
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The hadronic decays of heavy quark-antiquark 13S1 resonances such as the $/J or T can provide an ideal laboratory for studying the properties of gluon jets. We discuss the predictions of QCD perturbation theory for gluon jet structures, hadronic multiplicities, fragmentation distributions, and angular distributions. In particular the channel (Qa) y + X, whose rate, spectrum, and angular distrib...
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The use of perturbation theory to describe radiative decays of quarkonia is based on the fact that, as long as the velocity v of the heavy quark is small, these decay processes involve two widely separated distance scales: the scale 1/(mv) over which the quark and antiquark bind into the quarkonium and the scale 1/m over which the quark-antiquark pair decays (with m the heavy quark mass). By ex...
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In this talk I present the results of two calculations that make use of Non-Relativistic QCD and the newly developed Soft-Collinear Effective Theory. The first process considered is inclusive radiative Υ decay. The second process considered is the leading color-octet contribution to e+e− → J/ψ + X . Bound states of heavy quarks and antiquarks have been of great interest since the discovery of t...
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ژورنال
عنوان ژورنال: Nuclear Physics B - Proceedings Supplements
سال: 2003
ISSN: 0920-5632
DOI: 10.1016/s0920-5632(02)01987-4