We compute the light hadron mass spectrum in quenched lattice QCD at β=6.0 using the Sheikholeslami-Wohlert fermionic action. The calculation is done
for several choices of the coefficient cSW, including cSW=0 and the
recently proposed optimal value cSW=1.769. We find that the individual
masses change by up to 30\% under O(a) improvement. The spectrum calculation
suggests cSW≈1.4 for the optimal value of the coefficient.Comment: 15 pages, uuencoded Z-compressed postscript file. Also available from
http://www.desy.de/pub/preprints/desy/199