2017/06/16 by Kostas Orginos, Anatoly Radyushkin, Orginos, Kostas +5 · 8 citations
Physics and Astronomy · #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions #High-Energy Particle Collisions Research
paper · pdf · doi:10.48550/arxiv.1706.05373
We demonstrate a new method of extracting parton distributions from lattice calculations. The starting idea is to treat the generic equal-time matrix element \cal M (Pz3, z32) as a function of the Ioffe time ν= Pz3 and the distance z3. The next step is to divide \cal M (Pz3, z32) by the rest-frame density \cal M (0, z32). Our lattice calculation shows a linear exponential z3-dependence in the rest-frame function, expected from the Z(z32) factor generated by the gauge link. Still, we observe that the ratio \cal M (Pz3 , z32)/\cal M (0, z32) has a Gaussian-type behavior with respect to z3 for 6 values of P used in the calculation. This means that Z(z32) factor was canceled in the ratio. When plotted as a function of ν and z3, the data are very close to z3-independent functions. This phenomenon corresponds to factorization of the x- and k_⊥-dependence for the TMD \cal F (x, k_⊥2). For small z3 ≤ 4a, the residual z3-dependence is explained by perturbative evolution, with αs/π=0.1.