Nucleon helicity and transversity parton distributions from lattice QCD

• Published in: Nuclear physics. B Vol. 911; no. C; pp. 246 - 273
• Main Authors: Chen, Jiunn-Wei, Cohen, Saul D., Ji, Xiangdong, Lin, Huey-Wen, Zhang, Jian-Hui
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2016; Elsevier
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/j.nuclphysb.2016.07.033

We present the first lattice-QCD calculation of the isovector polarized parton distribution functions (both helicity and transversity) using the large-momentum effective field theory (LaMET) approach for direct Bjorken-x dependence. We first review the detailed steps of the procedure in the unpolarized case, then generalize to the helicity and transversity cases. We also derive a new mass-correction formulation for all three cases. We then compare the effects of each finite-momentum correction using lattice data calculated at Mπ≈310 MeV. Finally, we discuss the implications of these results for the poorly known antiquark structure and predict the sea-flavor asymmetry in the transversely polarized nucleon.