Two-Mass Effects in Heavy Flavor Deep Inelastic Scattering
In this talk recent calculations of 2-mass effects for heavy flavor deep inelastic scattering at 3-loop order in the asymptotic region Q2>>mi2 in Mellin (N) and momentum fraction (x) space are presented. The 2-mass effects are important, since the mass ratio of the charm and bottom quark is not particularly small and therefore both quarks need to be decoupled simultaneously. These effects are calculated via massive operator matrix elements, which are also important matching coefficients in the variable flavor number scheme, being an important ingredient for the determination of the strong coupling constant αs(MZ) and the parton distribution functions using LHC data. In Mellin space, we find harmonic, generalized harmonic, cyclotomic and inverse binomially weighted nested sums, which give rise to iterated integrals over up to square root valued letters which can also depend on the mass ratio.