First Monte Carlo global analysis of nucleon transversity with lattice QCD constraints

TL;DR

This paper presents the first global analysis of nucleon transversity distributions combining SIDIS data with lattice QCD constraints on the tensor charge, revealing consistent results and specific quark contributions.

Contribution

It introduces a novel Monte Carlo nested sampling method for global QCD analysis incorporating lattice QCD constraints on the tensor charge.

Findings

Compatible transversity distributions with lattice QCD $g_T$ values.

Determined quark contributions: $u=0.3(2)$, $d=-0.7(2)$ at $Q^2=2$ GeV$^2$.

Contrasts with previous analyses that found smaller $g_T$ values.

Abstract

We report on the first global QCD analysis of the quark transversity distributions in the nucleon from semi-inclusive deep-inelastic scattering (SIDIS), using a new Monte Carlo method based on nested sampling and constraints on the isovector tensor charge $g_T$ from lattice QCD. A simultaneous fit to the available SIDIS Collins asymmetry data is compatible with $g_T$ values extracted from a comprehensive reanalysis of existing lattice simulations, in contrast to previous analyses which found significantly smaller $g_T$ values. The contributions to the nucleon tensor charge from $u$ and $d$ quarks are found to be $\delta u = 0.3(2)$ and $\delta d = -0.7(2)$ at a scale $Q^2 = 2$ GeV$^2$.