RECOLA: REcursive Computation of One-Loop Amplitudes

We present the Fortran95 program Recola for the perturbative computation of next-to-leading-order transition amplitudes in the Standard Model of particle physics. The code provides numerical results in the ’t Hooft–Feynman gauge. It uses the complex-mass scheme and allows for a consistent isolation of resonant contributions. Dimensional regularization is employed for ultraviolet and infrared singularities, with the alternative possibility of treating collinear and soft singularities in mass regularization. Recola supports various renormalization schemes for the electromagnetic and a dynamical Nf-flavour scheme for the strong coupling constant. The calculation of next-to-leading-order squared amplitudes, summed over spin and colour, is supported as well as the computation of colour- and spin-correlated leading-order squared amplitudes needed in the dipole subtraction formalism.本文提出一款用于粒子物理标准模型下次领头阶跃迁振幅微扰计算的Fortran95程序Recola。该程序采用’t Hooft-Feynman规范（’t Hooft–Feynman gauge）输出数值结果，运用复质量方案（complex-mass scheme），并可对共振贡献（resonant contributions）实现一致性分离。针对紫外奇点（ultraviolet singularities）与红外奇点（infrared singularities），程序采用维数正规化（dimensional regularization）方案，同时也支持通过质量正规化（mass regularization）处理共线奇点（collinear singularities）与软奇点（soft singularities）作为替代方案。Recola支持电磁相互作用的多种重整化方案（renormalization scheme），以及用于强耦合常数（strong coupling constant）计算的动力学N_f味方案。其不仅可完成对自旋与色自由度求和的次领头阶平方振幅（next-to-leading-order squared amplitudes）计算，还支持偶极减除形式体系（dipole subtraction formalism）所需的自旋与色关联领头阶平方振幅的计算。