Soft-Gluon Resummation for Heavy Quark Production in Charged-Current Deep Inelastic Scattering

TL;DR

Problem: soft-gluon radiation in heavy-quark production in charged-current DIS leads to large-x terms that destabilize fixed-order predictions. Approach: perform threshold resummation in MSbar coefficient functions to next-to-leading logarithmic accuracy, accounting for mass effects and matching to NLO. Findings: resummation enhances charm structure functions at large x, particularly at low Q^2, and reduces factorization/renormalization-scale dependence; the impact differs between massive and massless regimes. Implications: results inform NuTeV and HERA analyses and can improve PDF fits, though non-perturbative corrections remain to be incorporated.

Abstract

We study soft-gluon radiation for heavy quark production in charged-current Deep Inelastic Scattering processes. We resum large-x contributions to the MSbar coefficient function to next-to-leading logarithmic accuracy and present results for charm quark structure functions for several values of the ratio m_c/Q. The effect of the resummation turns out to be visible, especially at small Q^2, and the results exhibit very little dependence on factorization and renormalization scales. The impact of our calculation on structure function measurements at NuTeV and HERA experiments is discussed.

Figures (7)

• Figure 1: Results for $F_2^c(x,Q^2)$ for charm quark production in neutrino scattering at $Q^2=2$ GeV$^2$ with (solid) and without (dashed) soft resummation in the coefficient function. We have set $\mu_F=\mu=Q$.
• Figure 2: As in Fig. \ref{['q2']}, but for $Q^2=5$ GeV$^2$.
• Figure 3: Results for $F_2^c(x,Q^2)$ for positron-proton scattering at $Q^2=300$ GeV$^2$, with (solid) and without (dashes) soft resummation in the coefficient function. We have set $\mu_F=\mu=Q$. In the inset figure, we show the same plots at large $x$ and on a linear scale.
• Figure 4: As in Fig. \ref{['q300']}, but for $Q^2=1000$ GeV$^2$.
• Figure 5: Dependence of $F_2^c$ on the factorization scale for neutrino scattering at $Q^2=2$ GeV$^2$. Solid lines include soft resummation in the coefficient function, dashed lines are fixed-order predictions.