Mesons in large-N QCD

TL;DR

This paper systematically studies meson spectra and decay constants across different N in large-N QCD using lattice simulations, providing insights into the behavior of mesons as N varies.

Contribution

It offers the first comprehensive lattice computation of meson properties for N=2 to N=17 in the quenched approximation, including extrapolations to the large-N limit.

Findings

Meson masses and decay constants vary smoothly with N.

Results agree with some holographic predictions.

Provides data for N-dependent meson spectra in large-N QCD.

Abstract

We present the results of a systematic, first-principles study of the spectrum and decay constants of mesons for different numbers of color charges N, via lattice computations. We restrict our attention to states in the non-zero isospin sector, evaluating the masses associated with the ground-state and first excitation in the pseudoscalar, vector, scalar, and axial vector channels. Our results are based on a new set of simulations of four dimensional SU(N) Yang-Mills theories with the number of colors ranging from N=2 to N=17; the spectra and the decay constants are computed in the quenched approximation (which becomes exact in the 't Hooft limit) using Wilson fermions. After discussing the extrapolations to the chiral and large-N limits, we present a comparison of our results to some of the numerical computations and analytical predictions available in the literature - including, in particular, those from holographic computations.