Invariant-mass distribution of top-quark pairs and top-quark mass determination

TL;DR

This paper improves the theoretical prediction of the top-quark pair invariant-mass distribution near threshold by resumming non-relativistic corrections, leading to more accurate top-quark mass determination.

Contribution

The authors derive a factorization formula to resum non-relativistic corrections at next-to-leading power, enhancing the precision of top-quark mass measurements.

Findings

Resummation significantly increases the differential cross section near threshold.

The improved prediction aligns better with experimental data.

Using this method yields a top-quark mass estimate closer to direct measurements.

Abstract

We investigate the invariant-mass distribution of top-quark pairs near the $2m_t$ threshold, which has strong impact on the determination of the top-quark mass $m_t$. We show that higher-order non-relativistic corrections lead to large contributions which are not included in the state-of-the-art theoretical predictions. We derive a factorization formula to resum such corrections to all orders in the strong-coupling, and calculate necessary ingredients to perform the resummation at next-to-leading power. We combine the resummation with fixed-order results and present phenomenologically relevant numeric results. We find that the resummation effect significantly enhances the differential cross section in the threshold region, and makes the theoretical prediction more compatible with experimental data. We estimate that using our prediction in the determination of $m_t$ will lead to a value closer to the result of direct measurement.