自发破缺规范理论中的光子-光子散射

本文在SU(2)_L×U(1)模型里研究中间态的W介子对光子-光子散射的贡献。由于自发破缺规范理论的可重整化性以及自发破缺以后电磁规范不变性仍成立,在单迴路近似下,光子-光子散射幅中的无穷大必然互相抵消。本文用具体计算说明这一点,并且在低能近似下给出电磁场的等效非线性相互作用拉格朗日量和散射截面。在低能近似下,轻子中间态对散射的贡献为主,然而在高能极限下,W介子中间态的贡献将变得可以和轻子中间态的贡献相比较。

PHOTON-PHOTON SCATTERING IN SPONTANEOUSLY BROKEN GAUGE THEORIES

We investigate the contributions of W-meson intermediate states to photon-photon scattering in SU(2)_L×U(1) model. Because the spontaneously broken gauge theories are renormalizable and the electromagnetic gauge invariance remains valid under symmetry-breaking, the infinities in the scattering amplitude of one loop approximation must cancel each other. We show the finiteness of the photon-photon scattering amplitude by calculation. We give the effective nonlinear interaction Lagrangian of the electromagnetic field and the scattering cross section at low energies. At low energies the leptonic intermediate states dominate the scattering amplitude, but at high energy limits the contributions of W-meson intermediate states are comparable with the contributions of leptonic intermediate states.