Prospects for observing the lowest-lying odd-parity ${\Sigma }_c$ and ${\Sigma }_b$ baryons

Abstract

There exist candidates for the negative-parity states ${\Lambda }_{c,b}(1/2^{-},3/2^{-})$ consisting of an isospin-zero, spin-zero light diquark $[ud]$ with one unit of orbital angular momentum with respect to a $c,b$ quark. However, there exists only one candidate for the orbital excitations of the ${\Sigma }_c(1/2^{+})$ and ${\Sigma }_c^{\ast }(3/2^{+})$, and none for the orbital excitations of ${\Sigma }_b(1/2^{+})$ or ${\Sigma }_b^{\ast }(3/2^{+})$. We extend a previous discussion of odd-parity ${\Lambda }_{c,b}$ states and explore some patterns of the odd-parity ${\Sigma }_{c,b}$ baryons consisting of a light isospin-one nonstrange diquark $(uu,ud,dd)$ in a state of $L=1$ with respect to the spin-1/2 heavy quark $(c,b)$.

Comments: 16 pages, 3 figures, submitted to Phys. Rev. D. Comparisons with lattice gauge theory predictions corrected