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arXiv · 1111.4249

Sivers and Boer-Mulders observables from lattice QCD

B. U. Musch·Ph. Hägler·M. Engelhardt·J. W. Negele·A. Schäfer
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Abstract

We present a first calculation of transverse momentum dependent nucleon observables in dynamical lattice QCD employing non-local operators with staple-shaped, "process-dependent" Wilson lines. The use of staple-shaped Wilson lines allows us to link lattice simulations to TMD effects determined from experiment, and in particular to access non-universal, naively time-reversal odd TMD observables. We present and discuss results for the generalized Sivers and Boer-Mulders transverse momentum shifts for the SIDIS and DY cases. The effect of staple-shaped Wilson lines on T-even observables is studied for the generalized tensor charge and a generalized transverse shift related to the worm gear function g_1T. We emphasize the dependence of these observables on the staple extent and the Collins-Soper evolution parameter. Our numerical calculations use an n_f = 2+1 mixed action scheme with domain wall valence fermions on an Asqtad sea and pion masses 369 MeV as well as 518 MeV.

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B. U. Musch, Ph. Hägler, M. Engelhardt, J. W. Negele, A. Schäfer. 2012-07-16. Sivers and Boer-Mulders observables from lattice QCD. https://doi.org/10.1103/physrevd.85.094510

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