出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We present the results of the O(
s) two-loop virtual corrections to the differential
decay width d(B ! Xs`+`−)=d^s, where ^s is the invariant mass squared of the
lepton pair, normalized to m2
b . Those contributions from gluon bremsstrahlung which
are needed to cancel infrared and collinear singularities are also included. Our calculation
is restricted to the range 0:05 ^s 0:25 where the e
ects from resonances are
small. The new contributions drastically reduce the renormalization scale dependence of
existing results for d(B ! Xs`+`−)=d^s. The renormalization scale uncertainty of the
corresponding branching ratio (restricted to 0:05 ^s 0:25) gets reduced from 13%
to 6:5%.
