epsilon: A tool to find a canonical basis of master integrals

In 2013, Henn proposed a special basis for a certain class of master integrals, which are expressible in terms of iterated integrals. In this basis, the master integrals obey a differential equation, where the right hand side is proportional to ϵ in d=4−2ϵ space–time dimensions. An algorithmic approach to find such a basis was found by Lee. We present the tool epsilon, an efficient implementation of Lee’s algorithm based on the Fermat computer algebra system as computational back end.