Successes and Failures of a More Comprehensive Hard Wall AdS/QCD

TL;DR

This paper enhances the hard wall AdS/QCD model by including tensor fields and interactions up to dimension six, analyzing spectrum modifications, decay rates, and couplings, and evaluating the model's alignment with QCD data.

Contribution

It introduces new tensor field interactions into the hard wall AdS/QCD model and assesses their impact on meson spectra and decay properties.

Findings

Breaking chiral symmetry modifies the meson spectrum.

The model's predictions for decay rates align with experimental data.

The fit yields a QCD quark condensate magnetic susceptibility consistent with phenomenology.

Abstract

We explore corrections to the "hard wall" gravity dual of QCD with two-form tensor fields. These fields correspond to a dimension three quark bilinear in QCD, which generates states with 1(--) and 1(+-) quantum numbers, or omega/rho-like and h1/b1-like mesons, respectively. We include new interaction terms, which render the model complete up to dimension six. We find that breaking chiral symmetry induces modifications to the spectrum, by mixing the vector current and the new two-tensor operator. This breaks the degeneracy of the 1(--) and 1(+-) spectra. We also compute the (b1->omega + pi) decay rate and D/S ratio, and the couplings of excited rho states to two pions. We then perform a comprehensive new fit to QCD data. We obtain a value for the magnetic susceptibility of the QCD quark condensate which is consistent with phenomenological estimates. These results allow us to evaluate the success of dimension counting and UV matching in this model.