ZHANG SHENGXI, ZHANG ZHENYU, LIU JUEPING. Dependence of Form Factors of γγ*→π0 Transition to the Finiteness of the Resonance Widths. [J]. 2007, (1): 63-66.
ZHANG SHENGXI, ZHANG ZHENYU, LIU JUEPING. Dependence of Form Factors of γγ*→π0 Transition to the Finiteness of the Resonance Widths. [J]. 2007, (1): 63-66.DOI:
In the framework of the local quantum chromodynamics sum rules
instead of the usual zero-width approximation
the finite-width approximation for the resonances
the ρ-ω mesons
is used to investigate the form factor of the transition γγ*→π0.According to the method of the analytic continuation by duality
the weight function
the polynomial of a low order N
is added to the dispersion integral to annihilate the integrand in the region where both resonance saturation and the QCD asymptotic expression are least reliable.The resultant form factor in the cases for the zero-and finitewidths are almost the same
and agree well with the experimental measurements
it thus shows a weak dependence of the form factor on the finiteness of the widths of the resonances
and justifies the correctness of the asymptotic form of the pion light-cone wave function.
关键词
量子色动力学定域光锥求和规则形状因子
Keywords
quantum chromodynamicslocal light-cone sum ruleform factor