A simulation study on the measurement of D~0-■ mixing parameter y at BESⅢ

We established a method on measuring the D0-■ mixing parameter y for BESⅢ experiment at the BEPCⅡ e+e-collider. In this method, the doubly tagged ψ(3770) → D0■ events, with one D decays to CP-eigenstates and the other D decays semileptonically, are used to reconstruct the signals. Since this analysis requires good e/π separation, a likelihood approach, which combines the dE/dx, time of flight and the electromagnetic shower detectors information, is used for particle identification. We estimate the sensitivity of the measurement of y to be 0.007 based on a 20 fb-1 fully simulated MC sample.