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— | preprints:2000:ttp00-22 [2016/03/17 11:03] (current) – created - external edit 127.0.0.1 |
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| ====== TTP00-22 Kinematic Effects in Radiative Quarkonia Decays ====== |
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| <hidden TTP00-22 Kinematic Effects in Radiative Quarkonia Decays > Non-relativistic QCD (NRQCD) predicts colour octet contributions to be |
| significant not only in many production processes of heavy quarkonia but |
| also in their radiative decays. We investigate the photon energy |
| distributions in these processes in the endpoint region. There the velocity |
| expansion of NRQCD breaks down which requires a resummation of an infinite |
| class of colour octet operators to so-called shape functions. We model these |
| non-perturbative functions by the emission of a soft gluon cluster in the |
| initial state. We found that the spectrum in the endpoint region is poorly |
| understood if the values for the colour octet matrix elements are taken as |
| large as indicated from NRQCD scaling rules. Therefore the endpoint region |
| should not be taken into account for a fit of the strong coupling constant |
| at the scale of the heavy quark mass. |
| </hidden> |
| |**Stefan Wolf** | |
| |** Phys. Rev. D63 074020 2001 ** | |
| | {{preprints:2000:ttp00-22.pdf|PDF}} {{preprints:2000:ttp00-22.ps|PostScript}} [[http://arxiv.org/abs/hep-ph/0010217|arXiv]] | |
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