The Light Hadron Spectrum and Decay Constants in Quenched Lattice QCD

TL;DR

This study uses quenched lattice QCD to compute light hadron masses and decay constants, achieving results close to experimental values and providing insights into hadron structure within a simplified computational framework.

Contribution

The paper presents quenched lattice QCD calculations of light hadron masses and decay constants using an improved fermion action, with results comparable to experimental data.

Findings

Hadron masses within 2-3 standard deviations of experimental values.

Decay constant ratios close to experimental estimates.

Results demonstrate the effectiveness of quenched lattice QCD for hadron spectroscopy.

Abstract

We present results for light hadrons composed of both degenerate and non-degenerate quarks in quenched lattice QCD. We calculate masses and decay constants using 60 gauge configurations with an $O(a)$--improved fermion action at $\beta = 6.2$. Using the $\rho$ mass to set the scale, we find hadron masses within two to three standard deviations of the experimental values (given in parentheses): $m_{K^*}=868\er{9}{8}$~MeV (892~MeV), $m_{\phi}=970\err{20}{10}$~MeV (1020~MeV), $m_N=820\err{90}{60}$~MeV (938~MeV), $m_\Delta=1300\errr{100}{100}$~MeV (1232~MeV) and $m_\Omega=1650\err{70}{50}$~MeV (1672~MeV). Direct comparison with experiment for decay constants is obscured by uncertainty in current renormalisations. However, for ratios of decay constants we obtain $f_K/f_\pi=1.20\er{3}{2}$ (1.22) and $f_\phi/f_\rho=1.13\er{2}{3}$ (1.22).