Differences

This shows you the differences between two versions of the page.

@@ Line 1: / Line 1: @@
+====== TTP00-22 Kinematic Effects in Radiative Quarkonia Decays ======
+   <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]]   |
+| |