瞬子效应在0^(++)胶球的QCD求和规则中的作用

Effect of Instanton on the QCD Sum Rule of 0^(++) Glueball

利用包含瞬子效应的QCD求和规则计算了 0 + + 胶球的质量上限 ,结果为 1 3GeV .还探讨了变动瞬子参量时对QCD求和规则的影响 ,发现包含瞬子修正的QCD求和规则在瞬子大小为 1

In this paper, we investigate the instanton effects to the mass of 0 ++ glueball by QCD sum rule approach. The instantons are assummed to be free from each other and be with definite density varying with their sizes. We find the upper bound of mass of the 0 ++ glueball is 1 3GeV and very possibly the mass can be as low as 1GeV. Besides, the instanton effects greatly improve the stability of the sum rule and overtake the contribution of quarks and gluons condensate. The centre size of instantons at 1/3fm can give the stablest sum rule.