We compute the light-hadron mass spectrum at $\beta =5.7\mathrm{}$ using the $O\left(a\right)\mathrm{}$-improved Sheikholeslami-Wohlert fermion action with two choices of the clover coefficient: the classical value $c=1\mathrm{}$ and a mean-field or tadpole-improved estimate $c=1.57\mathrm{}$. We compare our results with those of the GF11 Collaboration who use the Wilson fermion action $\mathrm{}(c=0\mathrm{})\mathrm{}$. We find that changing $c$ from zero to 1 and 1.57 leads to significant differences in the masses of the chirally extrapolated and strange pseudoscalar and vector mesons, the nucleon, the $\Delta$, and also in the Edinburgh plot. A number of other quantities, for example, $m_V^2-m_P^2,\hspace{0.5em}J,\hspace{0.5em}{\mathrm{am}}_K{/am}_{\rho },$ and ${\mathrm{am}}_{K^{*}}{/am}_{\rho }$ do not appear to change significantly. We also investigate the effect of changing the lattice volume from approximately (2 ${\mathrm{f}\mathrm{m})}^3$ to (2.6 ${\mathrm{f}\mathrm{m})}^3$. We find that the meson masses are consistent to within one standard deviation and baryon masses are consistent to within two standard deviations.

• Received 14 August 1996

DOI:https://doi.org/10.1103/PhysRevD.55.1548