Masses and decay widths of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ξ</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>b</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi mathvariant="normal">Ξ</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>b</mml:mi></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math> baryons

Abstract

In this article, we present a complete classification of the negative parity ${\mathrm{\ensuremath{\Xi}}}_{c/b}^{\ensuremath{'}}$ and ${\mathrm{\ensuremath{\Xi}}}_{c/b}$ $P$-wave states: seven belonging to the $SU(3)$ flavor sextet and seven to the flavor antitriplet, the calculation of the ${\mathrm{\ensuremath{\Xi}}}_{c/b}^{\ensuremath{'}}$ and ${\mathrm{\ensuremath{\Xi}}}_{c/b}$ strong partial decay widths into ${^{2}\mathrm{\ensuremath{\Sigma}}}_{c}\overline{K}$, ${^{2}\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}\ensuremath{\pi}$, ${^{4}\mathrm{\ensuremath{\Sigma}}}_{c}\overline{K}$, ${^{4}\mathrm{\ensuremath{\Xi}}}_{c}^{\ensuremath{'}}\ensuremath{\pi}$, ${\mathrm{\ensuremath{\Lambda}}}_{c}^{\ensuremath{'}}\overline{K}$, ${\mathrm{\ensuremath{\Xi}}}_{c}\ensuremath{\pi}$, and ${\mathrm{\ensuremath{\Xi}}}_{c}\ensuremath{\eta}$ channels both within the elementary emission model and the $^{3}{P}_{0}$ model, and the calculation of the electromagnetic decay widths for ${\mathrm{\ensuremath{\Xi}}}_{c/b}^{\ensuremath{'}}$ and ${\mathrm{\ensuremath{\Xi}}}_{c/b}$ 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 ${\mathrm{\ensuremath{\Xi}}}_{c}(2923{)}^{0}$, ${\mathrm{\ensuremath{\Xi}}}_{c}(2939{)}^{0}$, and ${\mathrm{\ensuremath{\Xi}}}_{c}(2965{)}^{0}$ states, as well as for the ${\mathrm{\ensuremath{\Xi}}}_{c}$'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 ${\mathrm{\ensuremath{\Xi}}}_{c}$ states. Very recently the LHCb Collaboration reported the observation of two new ${\mathrm{\ensuremath{\Xi}}}_{b}$ states, namely ${\mathrm{\ensuremath{\Xi}}}_{b}(6327{)}^{0}$ and ${\mathrm{\ensuremath{\Xi}}}_{b}(6333{)}^{0}$, in the ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ 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 ${\mathrm{\ensuremath{\Xi}}}_{b}$ system with ${J}_{{\mathrm{\ensuremath{\Xi}}}_{b}(6327{)}^{0}}^{P}=3/{2}^{+}$ and ${J}_{{\mathrm{\ensuremath{\Xi}}}_{b}(6333{)}^{0}}^{P}=5/{2}^{+}$.

Topics & Concepts