Top quark production near threshold and the top quark mass

TL;DR

This paper analyzes top-anti-top production near threshold in electron-positron collisions, incorporating advanced corrections to improve the precision of top quark mass measurements, highlighting the importance of mass scheme choices.

Contribution

It introduces a NNLO calculation with resummed logarithms and advocates for a subtracted potential scheme to enhance top mass determination accuracy.

Findings

NNLO corrections significantly affect cross section peak

Using a subtracted potential improves mass measurement precision

Normalization uncertainties remain substantial

Abstract

We consider top-anti-top production near threshold in $e^+ e^-$ collisions, resumming Coulomb-enhanced corrections at next-to-next-to-leading order (NNLO). We also sum potentially large logarithms of the small top quark velocity at the next-to-leading logarithmic level using the renormalization group. The NNLO correction to the cross section is large, and it leads to a significant modification of the peak position and normalization. We demonstrate that an accurate top quark mass determination is feasible if one abandons the conventional pole mass scheme and if one uses a subtracted potential and the corresponding mass definition. Significant uncertainties in the normalization of the $t\bar{t}$ cross section, however, remain.