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, mc→ 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 MH/mc 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(MH/mc) 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.
Highlights
In this paper we focus on the latter process, pp → H + jetc
It can be expected that a reliable description of Higgs boson production in association with a charm jet can be obtained by systematically computing the different terms in eq (1.2) to higher orders in perturbative QCD
We emphasize that the transformation from “massive” to conventional MS parton distribution functions is important in our construction because “massive” PDFs are not known phenomenologically and, as we have shown in section 2, the two PDFs start being different at order O(αs)
Summary
Parton distribution functions are traditionally defined in the MS scheme and employ massless on-shell partons. When the subtracted terms are added back and integrated over unresolved parts of the Hg phase space, logarithms of the charm mass appear This procedure is identical to methods developed to extract infrared and collinear singularities from real emission contributions to partonic cross sections. Since mc is just a collinear regulator, results for short-distance hadronic cross sections should be the same, independent of whether one starts with nearly massive or massless charm quarks. This requirement allows us to derive a relation between the “massive” and the MS PDFs. This requirement allows us to derive a relation between the “massive” and the MS PDFs
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