Charm lifetime

Summary

A review of the charmed meson and baryon lifetimes is presented. Our knowledge of charmed-particle lifetimes has greatly improved over the past two years, a crucial role having been played by the E687 experiment at Fermilab, which has almost quadrupled the samples of D mesons. The lifetime ratiosτ(D⁺)/τ(D⁰) andτ(D ⁺_s )/τ(D⁰) are now known with an accuracy of 1.7% and 3.7%, respectively. In the baryon sector the statistics is still limited, but the experimental results on Λ ⁺_c , Ξ ⁰_c and Ξ ⁺_c exhibit a clear pattern of lifetime hierarchy, as expected from simple theoretical arguments. The first measurement ofτ(Ω ⁰_c ) from E687 is also presented to complete the charmed-baryon lifetime picture. The more accurate experimental scenario can provide information on non-perturbative QCD effects and the hadronic matrix elements.