Light pseudoscalar and axial spectroscopy using AdS/QCD modified soft wall model

Abstract

We describe the mass spectrum of light pseudoscalar and axial mesons in the context of the modified soft wall model with an extra UV cutoff. In order to include the pseudoscalar and axial states, we define an anomalous dimension that shifts the conformal dimension of the non-interacting bulk fields such that the parity behavior of those states is included, thus inducing chiral symmetry breaking. This idea contrasts with the usual approach that uses interacting scalar, vector and axial bulk fields to give rise the spectrum. Using the extra UV cutoff approach, we can fit six η and six a1 organized in radial trajectories with an RMS error close to 21.1%. We also confirm that chiral symmetry is restored in this model after checking that highly excited ρ and a1 states become degenerate.