489 research outputs found
Towards the NNLL precision in
The present NLL prediction for the decay rate of the rare inclusive process
has a large uncertainty due to the charm mass
renormalization scheme ambiguity. We estimate that this uncertainty will be
reduced by a factor of 2 at the NNLL level. This is a strong motivation for the
on-going NNLL calculation, which will thus significantly increase the
sensitivity of the observable to possible new degrees
of freedom beyond the SM. We also give a brief status report of the NNLL
calculation.Comment: 5 pages, 2 figures, contribution to the proceedings of EPS-HEP 200
Reduction of Charm Quark Mass Scheme Dependence in at the NNLL Level
The uncertainty of the theoretical prediction of the
branching ratio at NLL level is dominated by the charm mass renormalization
scheme ambiguity. In this paper we calculate those NNLL terms which are related
to the renormalization of , in order to get an estimate of the
corresponding uncertainty at the NNLL level. We find that these terms
significantly reduce (by typically a factor of two) the error on induced by the definition of . Taking into account the
experimental accuracy of around 10% and the future prospects of the
factories, we conclude that a NNLL calculation would increase the sensitivity
of the observable to possible new degrees of freedom
beyond the SM significantly.Comment: 13 pages including 3 figure
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