Collier: a fortran-based Complex One-Loop LIbrary in Extended Regularizations

We present the library COLLIER for the numerical evaluation of one-loop scalar and tensor integrals in perturbative relativistic quantum field theories. The code provides numerical results for arbitrary tensor and scalar integrals for scattering processes in general quantum field theories. For tensor integrals either the coefficients in a covariant decomposition or the tensor components themselves are provided. COLLIER supports complex masses, which are needed in calculations involving unstable particles. Ultraviolet and infrared singularities are treated in dimensional regularization. For soft and collinear singularities mass regularization is available as an alternative.本研究提出了用于微扰相对论量子场论中一圈标量与张量积分数值计算的COLLIER库。该代码可为一般量子场论中散射过程的任意张量与标量积分提供数值结果。针对张量积分，既可以提供协变分解下的系数项，也可直接输出张量分量本身。COLLIER库支持复质量设置，这在涉及不稳定粒子的计算中是必需的。紫外与红外奇点采用维度正规化方案处理；对于软与共线奇点，亦可选用质量正规化方案作为替代方案。