On new physics in ΔΓ d

Motivated by the recent measurement of the dimuon asymmetry by the DØ 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 ΔΓ d . In particular, we perform model-independent studies of non-standard effects associated to the dimension-six current-current operators ( d̄p )( p̄ ′b) with p, p′ = u, c as well as ( d̄p )( τ̄τ ). In both cases we find that for certain flavour or Lorentz structures of the operators sizeable deviations of ΔΓ d away from the Standard Model expectation cannot be excluded in a model-independent fashion.