On the determination of Δm and ΔΓ in tagged [formula omitted] decays

Abstract

We consider the time dependence of the decays of tagged D 0 and D 0 to arbitrary decay modes. We expand each decay width as exp(− Γt) times a series in Γt, where Γ is the average decay width of the mass eigenstates D h and D l , and examine the first three terms of the series. We show that experimental information on the coefficients of these terms allows in principle to compute the mixing parameters Δm, ΔΓ and η = | q p | i.e., the mass and decay-width differences of mass eigenstates, and CP violation in mixing. In particular, we discuss the possibility of extracting these parameters if one disposes of the measurement of the time-dependent decay widths of D 0(t) D 0(t) to a single final state f and make a comparison with the situation when information about two different final states f and f′ is available.