Generalized Lüscher’s formula in baryon-meson and baryon-baryon scattering with twisted boundary condition

Lüscher’s formula establishes the relationship between the scattering phase shift and the two-particle energy levels in a finite cubic box. The original formula was obtained for elastic scattering of two massive spinless particles with the periodic boundary condition in the Center Of Mass (COM) frame. In this paper, using non-relativistic quantum mechanics, we consider both spin-1/2 particle-spinless particle scattering and spin-1/2 particle-spin-1/2 particle scattering in the COM frame with the twisted boundary condition below and above the inelastic threshold. Generalized relations between energy levels of two-particle system and the scattering phase shift are established.