Spectrum of singly heavy baryons from a chiral effective theory of diquarks

The mass spectra of singly charmed and bottom baryons, $Lambda_{c/b}(1/2^pm,3/2^-)$ and $Xi_{c/b}(1/2^pm,3/2^-)$, are investigated using a nonrelativistic potential model with a heavy quark and a light diquark. The masses of the scalar and pseudoscalar diquarks are taken from a chiral effective theory. The effect of $U_A(1)$ anomaly induces an inverse hierarchy between the masses of strange and non-strange pseudoscalar diquarks, which leads to a similar inverse mass ordering in $rho$-mode excitations of singly heavy baryons.