Speaker
Description
In this talk, we discuss two aspects of the ongoing efforts of the CTEQ–TEA group toward global parton distribution function (PDF) analyses beyond NNLO in QCD.
First, we present the realization of an intermediate ACOT-like general-mass variable flavor number (GMVFN) scheme for deep-inelastic scattering (DIS) at approximate next-to-next-to-next-to-leading order (aN$^3$LO) in QCD. Using the DIS structure functions $F^{c,b}_{2,L}$, we illustrate the main features of this scheme and discuss our ongoing work toward the full ACOT-MPS formulation at N$^3$LO.
Second, we present a generalization of the $x$-space Candia algorithm to N$^3$LO in QCD for solving the DGLAP evolution equations for unpolarized parton densities in the nucleon. The algorithm is based on logarithmic expansions of the solution and can be extended to all orders in QCD. An expansion equivalent to the exact DGLAP solution at N$^3$LO is presented in the non-singlet sector. We show results for approximate N$^3$LO PDFs evolved using the most recent approximations to the N$^3$LO splitting functions, together with a benchmark comparison against the HOPPET-v2 code.
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