Heavy Quark Initiated Contributions to Deep Inelastic Structure Functions
S. Kretzer, I. Schienbein
TL;DR
This work computes $O(\alpha_s^1)$ heavy-quark initiated contributions to deep inelastic structure functions within the ACOT framework, maintaining full heavy-quark mass dependence and introducing a subtraction term to ensure convergence to the massless ${\overline{\rm MS}}$ results at large $Q^2$. The authors derive LO and NLO contributions, incorporate gluon-fusion terms with appropriate subtractions for quasi-collinear logs, and provide a consistent prescription for combining heavy-quark scattering and GF processes. Numerical results for NC and CC DIS show that NC charm is numerically small overall, though $QS^{(1)}$ effects can be sizable at certain scales; CC charm, however, exhibits substantial quark-initiated corrections that can rival gluon-initiated ones, especially at high factorization scales. The findings guide the treatment of heavy quark densities in global analyses and emphasize the role of scale choices and subtraction terms in achieving a reliable, MSbar-consistent description of heavy-quark contributions to DIS.
Abstract
We present O(alpha_s^1) corrections to deep inelastic scattering amplitudes on massive quarks obtained within the scheme of Aivazis, Collins, Olness and Tung (ACOT). After identifying the correct subtraction term the convergence of these contributions towards the analogous coefficient functions for massless quarks, obtained within the modified minimal subtraction scheme (MSbar), is demonstrated. Furthermore, the quantitative relevance of the contributions to neutral current (NC) and charged current (CC) structure functions is investigated for several choices of the factorization scale.