THEP group sets world record in one-loop computations
For the first time ever a physical observable depending on a one-loop eight-point function has been calculated!
The group of Prof. Dr. Stefan Weinzierl at the Physics Institute (WA THEP) of the University of Mainz recently published a numerical computation of jet rates for the process e+e- → n jets with up to n = 7 at next-to-leading order (NLO) accuracy in the strong coupling and in the leading color approximation.
Precision calculations in particle physics rely on the computation of higher order terms within perturbation theory. At the second order of perturbation theory, virtual one-loop Feynman diagrams – like the one shown here – occur. As the number of external particles increases, these diagrams become more and more difficult to calculate.
Technically, the new algorithm is based on the extension of the subtraction method to virtual one-loop diagrams, a suitable deformation of the one-loop integration contour and the efficient use of recursion relations. All integrals are performed numerically by Monte Carlo integration on a high-performance
cluster at the University of Mainz. For further details one can find the e-print version of the publication under
The members of the group of Prof. Dr. Stefan Weinzierl are Sebastian Becker, Daniel Götz, Christian Reuschle and Christopher Schwan – all of them Ph.D. students – who are working on various aspects of the numerical and automatized evaluation of high-energy precision physics observables.