It is found that nonspectator interactions between $c$ and $d$ quarks in the ${{\Lambda }_c}^{+}$ give a substantial enhancement of its decay rate. The lifetime relation $\frac{\tau \left({{\Lambda }_c}^{+}\right)}{\tau \left(D^{+}\right)}={[1+\frac{\tau \left(D^{+}\right)}{(3\mathrm{}\times {10}^{-13\mathrm{}} \mathrm{s})}]}^{-1\mathrm{}}$ is derived, based on the assumption that the $D^{+}$ decays purely via charm quark decay. The semileptonic branching fractions are related by $B_l\left({{\Lambda }_c}^{+}\right)=B_l\left(D^{+}\right)\times \frac{\tau \left({{\Lambda }_c}^{+}\right)}{\tau \left(D^{+}\right)}$.

• Received 21 November 1979

DOI:https://doi.org/10.1103/PhysRevLett.44.226