First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

P. C. Barry; A. Prokudin; T. Anderson; C. Cocuzza; L. Gamberg; W. Melnitchouk; E. Moffat; D. Pitonyak; J. -W. Qiu; N. Sato; A. Vladimirov; R. M. Whitehill

First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

P. C. Barry, A. Prokudin, T. Anderson, C. Cocuzza, L. Gamberg, W. Melnitchouk, E. Moffat, D. Pitonyak, J. -W. Qiu, N. Sato, A. Vladimirov, R. M. Whitehill

Abstract

We present the first simultaneous global QCD analysis of unpolarized transverse momentum dependent (TMD) and collinear parton distribution functions (PDFs) in the proton. Our study incorporates data from deep-inelastic scattering, Drell-Yan, inclusive weak boson, $W$+\,charm, and jet production involving PDFs, as well as TMD Drell-Yan and $Z$-boson production data from fixed target and collider experiments sensitive to both TMD and collinear distributions. The analysis is performed at next-to-next-to-leading logarithmic accuracy for QCD resummation in TMD observables and next-to-leading order for observables described in collinear factorization. The combined analysis improves knowledge of both TMD and collinear PDFs, particularly in the sea-quark sector, providing a consistent simultaneous description of the aforementioned observables.

First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

Abstract

+\,charm, and jet production involving PDFs, as well as TMD Drell-Yan and

-boson production data from fixed target and collider experiments sensitive to both TMD and collinear distributions. The analysis is performed at next-to-next-to-leading logarithmic accuracy for QCD resummation in TMD observables and next-to-leading order for observables described in collinear factorization. The combined analysis improves knowledge of both TMD and collinear PDFs, particularly in the sea-quark sector, providing a consistent simultaneous description of the aforementioned observables.

Paper Structure (8 equations, 4 figures, 1 table)

This paper contains 8 equations, 4 figures, 1 table.

Figures (4)

Figure 1: Comparison of a representative bin of the ATLAS 8 TeV data with the $\rm JAM25_{PDF+TMD}$ analysis at the 68% CI.
Figure 2: Comparison of relative errors for collinear $\bar{u} + \bar{d}$ (left panel) and $s + \bar{s}$ (right panel) PDFs between the baseline PDF (blue) and $\rm JAM25_{PDF+TMD}$ (red) analyses at $Q^2=10$ GeV$^2$ for 95% CIs.
Figure 3: TMDs $\tilde{f}_{q/p}(x,b_T)$ (upper panels) and ratios to the mean values of $\tilde{f}_{q/p}$ (bottom panels) as functions of $b_T$ for $u$, $\bar{u}$, and $s$ quarks at fixed $x=0.2$, 0.4, and 0.1, respectively, and $Q=10$ GeV. The $\rm JAM25_{PDF+TMD}$ results (red) are compared with the baseline TMD (yellow) and baseline TMD+LHC (green) analyses for 95% CIs.
Figure 4: Collins-Soper kernels ${\mathcal{D}}(b_T,Q)$ at $Q=10$ GeV at 95% CIs, with notations as in Fig. \ref{['f.TMD']}. The inset compares the 68% CI $\rm JAM25_{PDF+TMD}$ results with lattice QCD (ASWZ LQCD) data at $Q=2$ GeV Avkhadiev:2024mgd. (The lattice data were originally presented in Ref. Avkhadiev:2024mgd as $\gamma_q \equiv -2 \mathcal{D}$.)