Connected and Disconnected Sea Partons from CT18 Parametrization of PDFs

TL;DR

This paper introduces a new parametrization of parton distribution functions that distinguishes between connected and disconnected sea partons, incorporating lattice constraints and recent experimental data, providing detailed momentum fractions for various partons.

Contribution

It presents the first separation of connected and disconnected sea partons in the CT18 PDFs, using lattice constraints and small x behavior, enhancing understanding of hadronic structure.

Findings

Separated momentum fractions for valence, connected sea, and disconnected sea partons at 1.3 GeV.

Impact of SeaQuest data on the ar(x)-ar(x) distribution.

Comparison of parton momentum fractions with lattice calculations.

Abstract

The separation of the connected and disconnected sea partons, which were uncovered in the Euclidean path-integral formulation of the hadronic tensor, is accommodated with an alternative parametrization of the non-perturbative parton distribution functions in the CT18 global analysis. This is achieved with the help of the distinct small $x$ behaviours of these two sea partons and the constraint from the lattice calculation of the ratio of the strange momentum fraction to that of the $\bar u$ or $\bar d$ in the disconnected insertion. The whole dataset of CT18 is used in this CT18CS fit. The impact of the recent SeaQuest data on the $\bar{d}(x)-\bar{u}(x)$ distribution of CT18CS is also discussed. The separate momentum fractions for the valence, the connected sea and disconnected sea of $u$ and $d$, the strange and the gluon partons are presented at $\mu =1.3$ GeV for the first time. They can be compared term-by-term with systematic error controlled lattice calculations.