Threshold improved $Z H$ production at the LHC

TL;DR

This work addresses the precision prediction of associated $Z\!H$ production at the LHC by incorporating soft-gluon threshold resummation in both the gluon-fusion channel $gg\to ZH$ and the Drell–Yan type channel $q\bar q\to ZH$. The authors implement SV resummation in Mellin space and match to fixed-order results to obtain combined predictions at ${\cal O}(\alpha_s^3)$ accuracy, covering the total cross section and the $ZH$ invariant-mass distribution for $\sqrt{S}=13.6$ TeV. The gluon-initiated channel shows a substantial resummation-driven enhancement ($\sim 20$–$40\%$) with reduced scale uncertainties, while the DY-type channel remains near fixed-order values; the total cross section is about $1004$ fb with modest PDF and $\alpha_s$ uncertainties and most of the scale uncertainty arising from the $gg$ channel. These results yield robust, experimentally relevant predictions enabling improved comparisons with LHC measurements across the invariant-mass spectrum.

Abstract

We present precise theoretical results for the $ZH$ production cross section and invariant mass distribution at the Large Hadron Collider (LHC) taking into account the effects of soft gluons. We improve both quark-initiated and gluon-initiated subprocesses through threshold resummation within the QCD framework and present combined results relevant for $13.6$ TeV LHC.

Figures (2)

• Figure 1: The contribution from $gg$ subprocess is shown for fixed order and resummed cases with the corresponding uncertainties.
• Figure 2: The total contributions for the $pp \to ZH$ process (combination of DY-type and $gg$ subprocess) and the corresponding uncertainties.