Possible Explanation Why τ_{B^{\pm}}\simτ_{B^0} But τ_{D^{\pm}}\sim τ_{D^0}

Abstract

Data show that τ_{B^{\pm}}\simτ_{B^0}, but τ_{D^{\pm}}\sim 2τ_{D^0}. The naive interpretation which attributes τ_{D^{\pm}}\sim 2τ_{D^0} to a destructive interference between two quark diagrams for D^{\pm} decays, definitely fails in the B-case. We investigate Close and Lipkin's suggestion that the phases for producing radially excited states ψ_{2s} in the decay products of B-mesons can possess an opposite sign to the integrals for ψ_{1s} decay products. Their contributions can partially compensate each other to result in τ_{B^{\pm}}\simτ_{B^0}. Since D-mesons are much lighter than B-mesons, such possibilities do not exist in D-decays.