Masses and decay widths of Ξc/b and Ξ′c/b baryons

초록

In this article, we present a complete classification of the negative parity Xi'(c/b) and Xi(c/b) P-wave states: seven belonging to the SU(3) flavor sextet and seven to the flavor antitriplet, the calculation of the Xi'(c/b) and Xi(c/b) strong partial decay widths into (2)Sigma(c)(K) over bar, (2)Xi'(c)pi, (4)Sigma(c)(K) over bar, (4)Xi'(c)pi, Lambda'(c)(K) over bar, Xi(c)pi, and Xi(c)eta channels both within the elementary emission model and the P-3(0) model, and the calculation of the electromagnetic decay widths for Xi'(c/b) and Xi(c/b) radiative decays. By means of the equal-spacing mass rule and by the analysis of the strong partial decay widths, we suggest possible assignments for the new LHCb Xi(c)(2923)(0), Xi(c)(2939)(0), and Xi(c)(2965)(0) states, as well as for the Xi(c)'s previously reported by Belle and BABAR. Our results can be tested by future experiments, at LHCb and Belle, disentangling the remaining missing piece of information, i.e., the quantum numbers. Finally, a comparison is made between a three-quark and a quark-diquark description of Xi(c) states. Very recently the LHCb Collaboration reported the observation of two new Xi(b) states, namely Xi(b)(6327)(0) and Xi(b)(6333)(0), in the Lambda K-0(b)-pi(+) channel with a statistical significance larger than 9 standard deviations. The experimental masses and widths of these two states are consistent with our mass and width predictions for the doublet of D-wave excitations of the Xi(b) system with J(Xi b)(P)(6327)(0) = 3/2(+) and J(Xi b(6333)0)(P) = 5/2(+).

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