Combining the recent lattice calculation of $a_0(1450)$ and $\sigma(600)$ mesons with the overlap fermion in the chiral regime with the pion mass less than $300 {\rm MeV}$, the quenched lattice calculation of the scalar glueball, and the phenomenological s

PatternofLightScalarMesons5

model15)whichillustrateshowthescatteringstatemixeswiththeboundstateandgivesrisetothephaseshiftasthevolumeisincreased.Inasense,byvaryingthelatticevolume,hencethemomentum,onecanuseascatteringstatetomixwiththeboundstateandscantheenergyrangetoobtainthephaseshiftandthereforethewidthoftheresonance.Theinformationofthewidthcanalsobeobtainedbydetermininghowfarapartinenergythescatteringandboundstatestarttoavoidthelevelcrossing.

Tocalculatea0onthesamelattices,thetwo-quarkinterpolation eld