A global fit for αs(mZ) is performed on available e+e− data for the heavy jet mass distribution. The state-of-the-art theory prediction includes O(αs3) fixed-order results, N3LL′ dijet resummation, N2LL Sudakov shoulder resummation, and a first-principles treatment of power corrections in the dijet region. Theoretical correlations are incorporated through a flat random-scan covariance matrix. The global fit results in 0.1148−0.0022+0.0015, compatible with similar determinations from thrust and C-parameter. Dijet resummation is essential for a robust fit, as it engenders insensitivity to the fit-range lower cutoff; without resummation the fit-range sensitivity is overwhelming. In addition, we find evidence for a negative power correction in the trijet region if and only if Sudakov shoulder resummation is included.
@article{arxiv.2502.12253,
title = {A Precise Determination of $\alpha_s$ from the Heavy Jet Mass Distribution},
author = {Miguel A. Benitez and Arindam Bhattacharya and Andre H. Hoang and Vicent Mateu and Matthew D. Schwartz and Iain W. Stewart and Xiaoyuan Zhang},
journal= {arXiv preprint arXiv:2502.12253},
year = {2026}
}