We calculate next to leading order QCD corrections to the direct decays b → J/Ψ + X and b → η c + X. The strong renormalization scale dependence is seen to persist also in this order and in fact the rate is driven to an unphysical negative value at the M b scale. We show that this is a consequence of the strong suppression and scale dependence in the leading order term. Large cancellations take place between terms from three different orders in α s . Lacking a third order calculation we are forced to throw away the leading order term and all but one of the next to leading order terms. The remaining cc gluon emission term could very well be the dominant one. Even if this is not the case, the picture of a rate at least as suppressed as in the leading logarithmic approximation survives.
Abstract. We have studied three traveling vortex events during theof the vortices, differs from the classical picture of a traveling convection vortex. We therefore suggest that these vortex events might have a different generation mechanism or occur under a different state of the magnetosphere, and thus that they should be considered a separate class of events. The AMIE technique offers the possibility to relate the vortices to the large-scale convection patterns. We note how the vortices can be interpreted as small scale, rapid changes in the large-scale convection pattern, although these changes show many differences to previous studies of changing large-scale convection patterns. We speculate that this particular class of traveling vortex event may be generated by a perturbation in the separatric on the dayside magnetopause, caused by an enhancement or depreciation of the magnetic merging.
In Z 0 decay into prompt charmonium, i.e. charmonium not originating from B-meson decays, the most important contribution is expected to come from colour-octet mechanisms. However, previous fixed-order calculations of the colour-octet contribution contain large logarithms which, in a more complete treatment, should be resummed to all orders. We study this resummation by using a Monte Carlo QCD cascade model and find that the fixed-order colour-octet result is diminished by 15%. We compare the Monte Carlo calculations with results obtained by using analytical evolution equations.
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