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Description
We present a lattice QCD calculation of the nucleon unpolarized parton distribution functions (PDFs) at the physical point, with the nucleon boosted to $P_z = 1.78$ and $2.29$ GeV. At a lattice spacing $a = 0.076$ fm, these momenta correspond to $a P_z \lesssim 0.9$, so that lattice-discretization artifacts remain under control, in contrast to earlier physical-mass studies that reached larger nominal momenta at coarser spacings. The calculation is carried out on an $N_{\rm f} = 2+1$ ensemble and covers both the isovector and the connected isoscalar channels within the large-momentum effective theory (LaMET) framework. To reach these momenta with sufficient precision, we combine kinematically enhanced nucleon interpolating operators with Coulomb-gauge-fixed quark bilinears, which together suppress the excited-state contamination (ESC) at large $P_z$ and the signal-to-noise degradation at large quark separation. The light-cone PDFs are obtained through next-to-leading-order (NLO) perturbative matching supplemented by next-to-leading-logarithmic (NLL) renormalization-group resummation (RGR), and the matched distributions show good convergence between the two boosts. Combining the valence ($q-\bar{q}$) and full ($q+\bar{q}$) distributions, we reconstruct the quark and antiquark distributions over $x \in [-1, 1]$. The results are in good agreement with the CT18, MSHT20, and NNPDF4.0 global analyses in the moderate-$|x|$ window $0.25 \lesssim |x| \lesssim 0.75$. For the connected isoscalar channel, the antiquark (sea) distribution is substantially underestimated, an expected consequence of omitting the disconnected contributions, which are required for the physical flavor-singlet combination.