On new physics in ΔΓd

Motivated by the recent measurement of the dimuon asymmetry by the DO collaboration, which could be interpreted as an enhanced decay rate difference in the neutral B-d-meson system, we investigate the possible size of new-physics contributions to Delta Gamma(d) . In particular, we perform model-independent studies of non-standard effects associated to the dimension-six current-current operators ((d) over barp)((p) over bar 'b) with p, p' = u, c as well as ((d) over barb)((tau) over bar tau). In both cases we find that for certain flavour or Lorentz structures of the operators sizeable deviations of Delta Gamma(d) away from the Standard Model expectation cannot be excluded in a model-independent fashion.