Quenched Light Hadron Mass Spectrum and Decay Constants: the effects of $O(a)$-Improvement at $\beta =6.2$

We compare the light hadron spectrum and decay constants for quenched QCD at $\beta =6.2$ using an $O(a)$-improved nearest-neighbour Wilson fermion action with those obtained using the standard Wilson fermion action on the same set of 18 gauge configurations. For pseudoscalar meson masses in the range 330–800~MeV, we find no significant difference between the results for the two actions. The scales obtained from the string tension and mesonic sector are consistent, but differ from that derived from baryon masses. The ratio of the pseudoscalar decay constant to the vector meson mass increases slowly with quark mass as observed experimentally.