Using data recorded by the CLEO II and CLEO II.V detectors at CESR, we report new measurements of the [Formula: see text] and [Formula: see text] masses, and the first measurements of their intrinsic widths. The measured widths of these particles agree with the theoretical predictions. We also present a new measurement of the mass of the [Formula: see text] charmed baryon, observed by its decay into [Formula: see text], and the first observation of a new state which is identified as the [Formula: see text], the isospin partner of the previously discovered [Formula: see text] and [Formula: see text]. The quark model predicts many excited states of Λc and Σc baryons, some of which cannot, because of quantum mechanical conservations rules, decay via one pion to the ground state. We present results of a search for such states decaying via dipion decays into the ground state [Formula: see text] Recently, The CLEO collaboration also reported the existence of a pair of excited Ξc particles decaying into [Formula: see text]. These are thought to be orbitally excited Ξc' s with JP = 3/2-. Here we present a search for the analogous JP=1/2- particles, which are predicted to decay into [Formula: see text].
Framework for the chiral extrapolation of the charmed baryon ground-state masses
