On the interference of $ggH$ and $c\bar{c}H$ Higgs production mechanisms and the determination of charm Yukawa coupling at the LHC

TL;DR

This paper investigates the complex interference effects between different Higgs production mechanisms involving charm quarks at the LHC, highlighting the importance of QCD corrections and their unique behavior in the massless charm quark limit.

Contribution

It provides the first detailed analysis of QCD corrections to the interference between $ggH$ and $c\bar{c}H$ production mechanisms, revealing novel logarithmic behaviors.

Findings

QCD corrections involve logarithms of $M_H/m_c$

Interference contributions contain up to two powers of $\ln(M_H/m_c)$

Overall QCD correction impact is moderate due to cancellations

Abstract

Higgs boson production in association with a charm-quark jet proceeds through two different mechanisms - one that involves the charm Yukawa coupling and the other that involves direct Higgs coupling to gluons. The interference of the two contributions requires a helicity flip and, therefore, cannot be computed with massless charm quarks. In this paper, we consider QCD corrections to the interference contribution starting from charm-gluon collisions with massive charm quarks and taking the massless limit, $m_c \to 0$. The behavior of QCD cross sections in that limit differs from expectations based on the canonical QCD factorization. This implies that QCD corrections to the interference term necessarily involve logarithms of the ratio $M_H/m_c$ whose resummation is currently unknown. Although the explicit next-to-leading order QCD computation does confirm the presence of up to two powers of $\ln(M_H/m_c)$ in the interference contribution, their overall impact on the magnitude of QCD corrections to the interference turns out to be moderate due to a cancellation between double and single logarithmic terms.