Lifetimes of doubly charmed baryons: Xi(+)(cc) and Xi(++)(cc)

The total lifetimes of Xi(cc)(++) and Xi(cc)(+) baryons have been studied o n the basis of the operator-product expansion in the inverse charmed-quark mass, the matrix elements of the operators involved being estimated by usin g nonrelativistic QCD. This approach makes it possible to consider the spec tator decays of c quarks by systematically allowing for corrections associa ted with the fact that these quarks are bound in baryons and for correction s due to the Pauli interference contribution in the case of the Xi(cc)(++) baryon and to the electroweak-scattering contribution in the case of the Xi (cc)(+) baryon. Calculations along these lines have yielded the following e stimates: tau(Xi cc++) = 0.48 +/- 0.1 ps and tau(Xi cc+) = 0.12 +/- 0.01 ps .