A dynamical Einstein-Proca-dilaton holographic model and exotic hybrid meson resonances

Abstract

A fully dynamical Einstein-Proca-dilaton (EPD) holographic model is developed for the exotic $J^{PC}=1^{-+}$ hybrid meson, incorporating the backreaction of the massive vector field dual to the hybrid current in the bulk. Solving the coupled EPD system yields a self-consistent gravitational background and the mass spectrum of hybrid resonances. While the soft-wall limit reproduces linear Regge behavior, the inclusion of backreaction yields quantitative shifts that improve agreement with experimental candidates. The finite-temperature regime is approached by studying black hole thermodynamics and spectral functions across the confinement-deconfinement transition, fixing the Hawking-Page temperature to $T_c\sim 150\mathrm{MeV}$. Unlike non-backreacted AdS/QCD models, the dynamical background predicts a strong suppression of hybrid states already near the onset of deconfinement. These results demonstrate that gravitational backreaction has measurable consequences for both vacuum spectroscopy and in-medium properties of exotic hybrid mesons, emphasizing the relevance of a dynamical self-consistent approach in AdS/QCD.

arXiv comment33 pages, 10 figures