Two-loop virtual corrections to B → XSl+l- in the standard model

We calculate O(alpha (s)) two-loop virtual corrections to the differential decay width d Gamma (B --> X(s)l(+)l(-))/d (s) over cap, where (s) over cap the invariant mass squared of the lepton pair, normalized to m(b)(2). We also include those contributions from gluon bremsstrahlung which are needed to cancel infrared and collinear singularities present in the virtual corrections. Our calculation is restricted to the range 0.05 less than or equal to (s) over cap less than or equal to 0.25 where the effects from resonances are small. The new contributions drastically reduce the renormalization scale dependence of existing results for d Gamma (B --> X(s)l(+)l(-))/d (s) over cap. For the corresponding branching ratio (restricted to the above (s) over cap -range) the renormalization scale uncertainty gets reduced from similar to +/- 13% to similar to +/-6.5%. (C) 2001 Published by Elsevier Science B.V.