Flavor-Dependent Dynamical Spin-Orbit Coupling in Light-Front Holographic QCD: A New Approach to Baryon Spectroscopy

Abstract

We propose a novel extension of Light-Front Holographic Quantum Chromodynamics (LFHQCD) in which a flavor-dependent, dynamical spin–orbit potential is introduced at the level of the light-front Hamiltonian. The potential varies with the holographic coordinate and is motivated by the Gaussian localization of soft-wall modes and by heavy-quark symmetry, providing a unified treatment of short- and long-distance spin–orbit dynamics in both light and heavy baryons. An optional coupling to a holographic glueball background further enriches the nonperturbative structure of the model and enhances the description of excited states. The resulting modified light-front wave equation reproduces the observed flavor-dependent mass splittings and Regge trajectories, and yields substantially improved agreement with the baryon spectrum compared to flavor-independent holographic approaches. We present the analytic formulation, numerical implementation, and global parameter fits, together with phenomenological predictions relevant for ongoing and future heavy-baryon spectroscopy programs, including LHCb and Belle II. This soft-wall–compatible framework provides a unified and analytically transparent extension of LFHQCD that successfully incorporates dynamical spin–orbit effects across all quark flavors.