Strong and Electromagnetic Decays of Two New $Lambd{a}_c^{\ast }$ Baryons

Abstract

Two recently discovered excited charm baryons are studied within the framework of Heavy Hadron Chiral Perturbation Theory. We interpret these new baryons which lie $308\text{MeV}$ and $340\text{MeV}$ above the ${\Lambda }_c$ as $I=0$ members of a P-wave spin doublet. Differential and total decay rates for their double pion transitions down to the ${\Lambda }_c$ ground state are calculated. Estimates for their radiative decay rates are also discussed. We find that the experimentally determined characteristics of the ${\Lambda }_c^{\ast }$ baryons may be simply understood in the effective theory.

Comments: 16 pages with 4 figures not included but available upon request, CALT-68-1912