Virtual corrections to $gg\to ZH$ in the high-energy and large-$m_t$ limits

TL;DR

This paper calculates next-to-leading order virtual corrections for the gluon-gluon to ZH process in high-energy and large top-quark mass limits, employing Padé approximants to extend the validity of the expansion.

Contribution

It introduces a method using Padé approximants to improve the convergence of high-energy expansions in top-quark mass, providing precise results near the top pair threshold.

Findings

Accurate virtual corrections computed in high-energy and large-$m_t$ limits.

Padé approximants effectively extend the expansion's convergence.

Results applicable close to the top quark pair production threshold.

Abstract

We compute the next-to-leading order virtual corrections to the partonic cross-section of the process $gg\to ZH$, in the high-energy and large-$m_t$ limits. We use Pad\'e approximants to increase the radius of convergence of the high-energy expansion in $m_t^2/s$, $m_t^2/t$ and $m_t^2/u$ and show that precise results can be obtained down to energies which are fairly close to the top quark pair threshold. We present results both for the form factors and the next-to-leading order virtual cross-section.