NNLO zero-jettiness beam and soft functions to higher orders in the dimensional-regularization parameter $\epsilon$

Understand

We present the calculation of the next-to-next-to-leading order (NNLO) zero-jettiness beam and soft functions, up to the second order in the expansion in the dimensional regularization parameter $\epsilon$.

• These higher order terms are needed for the computation of the next-to-next-to-next-to-leading order (N$^3$LO) zero-jettiness soft and beam functions.
• As a byproduct, we confirm the $O(\epsilon^0)$ results for NNLO beam and soft functions available in the literature.