Charmed strange pentaquarks in the large Nc limit

The properties of pentaquarks containing a heavy antiquark and strange quarks are studied in the bound state picture. In the flavor SU(3) limit, there are many pentaquark states with the same binding energy. When the SU(3) symmetry-breaking effects are included, however, three states become particularly stable due to a open-quote open-quote Gell-Mann endash Okubo mechanism.close-quote close-quote They are the bar Qsuud and bar Qsudd states discussed by Lipkin, and a previously unstudied bar Qssud state. These states will have JP=1/2+ and their masses are estimated. These states, if they exist, may be seen in experiments in the near future. copyright 1996 The American Physical Society