We calculate the two-loop heavy quarkonium Hamiltonian within potential-NRQCD effective field theory in the non-annihilation channel. This calculation represents the first non-trivial step towards determining the N4LO Hamiltonian in the weak coupling regime. The large amount of computation is systematically handled by employing the β expansion, differential equations for master integrals, and adopting a single-step matching procedure, in contrast to the conventional two-step approach.
@article{arxiv.2407.00723,
title = {Two-loop Quarkonium Hamiltonian in Non-annihilation Channel},
author = {Go Mishima and Yukinari Sumino and Hiromasa Takaura},
journal= {arXiv preprint arXiv:2407.00723},
year = {2024}
}
Comments
5 pages, No figures; 2-loop Hamiltonian before expansion in eps added in Supplementary Material; minor modifications in the text; Version to appear in Phys$.$Rev$.$Lett