Chiral effective theory of scalar and vector diquarks revisited

Abstract: Chiral effective theory of light diquarks is revisited. We construct an effective Lagrangian based on the linear representation of three-flavor chiral symmetry. Here, we focus on the effect of a chiral and $U(1)_A$ symmetric term originated from an eight-point quark interaction. From this model, we obtain the mass formulas of scalar, pseudoscalar, vector, and axial-vector diquarks, which also describe the dependence of diquark masses on the spontaneous chiral symmetry breaking and the $U(1)_A$ anomaly. We regard singly heavy baryons as two-body systems composed of one heavy quark and one diquark and then predict the fate of the mass spectrum and the strong decay widths under chiral symmetry restoration.