Two-loop helicity amplitudes for fermion-fermion scattering
نویسنده
چکیده
We discuss the calculation of two-loop helicity amplitudes for quark-quark scattering in QCD and four-gluino scattering in N = 1 supersymmetric Yang-Mills theory. We study the dependence of the results on different variants of dimensional regularization. In particular, we consider the ’t Hooft-Veltman and four-dimensional helicity (FDH) schemes. We also discuss ambiguities in continuing the Dirac algebra to D dimensions. For the four-gluino case, once the infrared divergent part of the amplitude is subtracted, the finite remainder is free of these ambiguities.
منابع مشابه
One loop multiphoton helicity amplitudes.
We use the solutions to the recursion relations for double-off-shell fermion currents to compute helicity amplitudes for n-photon scattering and electronpositron annihilation to photons in the massless limit of QED. The form of these solutions is simple enough to allow all of the integrations to be performed explicitly. For n-photon scattering, we find that unless n = 4, the amplitudes for the ...
متن کاملScattering amplitudes with massive fermions using BCFW recursion
We study the QCD scattering amplitudes for q̄q → gg and q̄q → ggg where q is a massive fermion. Using a particular choice of massive fermion spinor we are able to derive very compact expressions for the partial spin amplitudes for the 2 → 2 process. We then investigate the corresponding 2 → 3 amplitudes using the BCFW recursion technique. For the helicity conserving partial amplitudes we again de...
متن کاملTwo-Loop Helicity Amplitudes for Quark-Quark Scattering in QCD and Gluino-Gluino Scattering in Supersymmetric Yang-Mills Theory
We present the two-loop QCD helicity amplitudes for quark-quark and quark-antiquark scattering. These amplitudes are relevant for next-to-next-to-leading order corrections to (polarized) jet production at hadron colliders. We give the results in the ‘t Hooft-Veltman and four-dimensional helicity (FDH) variants of dimensional regularization and present the scheme dependence of the results. We ve...
متن کاملLight-by-light scattering in SANC
In this paper we describe the implementation of the QED process γγ → γγ through a fermion loop into the framework of SANC system. The computations of this process takes into account non-zero mass of loop-fermion. We briefly describe additional precomputation modules used for calculation of massive fermion-box diagrams. We present the covariant and helicity amplitudes for this process and also s...
متن کاملCovariant One Loop Fermion Emission Amplitudes in Closed String Theories
We calculate the 2 fermionboson and the 4 fermion scattering amplitudes at the one loop in the NSR formulation of the heterotic and type II superstring theories using the covariant fermion emission vertex. The results are shown to agree with well known amplitudes calculated in the light-cone gauge in the GreenSchwarz formulation. The agreement of the 4 fermion amplitude entails the use of a new...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2004