纵向光子光锥波函数h_γ~∥(u,P^2)及其耦合常数

Longitudinal Photon Light-Cone Wave Function h_γ~∥(u,P^2) and Its Coupling

在量子色动力学(QCD)低能等效理论的框架中,利用瞬子媒质中的等效夸克传播子,在领头阶单圈水平上计算了与夸克-反夸克非局域张量流耦合的纵向光子光锥波函数hγ∥(u,P2)以及相应的耦合常数fγ∥(P2)的解析表达式,得到了包含扭度2和3贡献的光子光锥波函数hγ∥(u,P2)与夸克所分担的纵向动量份额u和光子虚度P2的关系,并考察了耦合常数fγ∥(P2)随P2的变化而变化的性状.结果表明,纵向波函数在不同虚度下都满足u1-u对称,而且相应的耦合常数与横向波函数的耦合常数在高能极限下趋于一致.

In the framework of the low-energy effective theory of quantum chromodynamics,using the expression of the quark propagator in the instanton medium,the explicit forms of light-cone longitudinal photon wavefunction hγ∥（u,P2） coupled with the quark-antiquark tensor non-local current,and the corresponding coupling constant fγ∥（u,P2） are calculated on the leading one-loop level. The behavior of hγ∥（u,P2） with the fraction u of the longitudinal momentum of the photon carried by a quark,u,and with the photon vatuality P2 are exploited,and the behavior of fγ∥（u,P2） with respect to P2 is investigated as well. The result shows that the longitudinal wave function with different virtualities are symmetric with the transformation u1-u,and the coupling constants fγ∥（u,P2） are consistent with the one corresponding to the transverse wave function in the high-energy limit.