We present results for the flavor non-singlet u-d parton distribution functions within the nucleon using the quasi-PDF approach.
The lattice calculation is performed by employing the twisted mass formulation and two gauge ensembles, having $N_f = 2$ and $N_f = 2 + 1 + 1$ dynamical fermions with masses tuned to their physical value.
For the $N_f = 2$ physical point ensemble, the unpolarized, helicity and transversity distributions are computed for three values of the nucleon momentum, namely [6, 8, 10]$\pi/L$ corresponding to [0.83,1.11,1.38] GeV.
Upon renormalization, we find that, as the nucleon momentum increases, the lattice results approach the phenomenological distributions resulting from analyses of deep inelastic scattering data, opening a promising path for a direct evaluation of parton distributions from the QCD Lagrangian.
Quasi-PDFs from Twisted mass fermions at the physical point · Around
J. J. Ethier et al., First simultaneous extraction of spin-dependent parton distributions and fragmentation functions from a global QCD analysis , Phys. Rev. Lett. 119 (2017) 132001 [ 1705.05889 ]