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arXiv · 0709.4293

Quark helicity flip and the transverse spin dependence of inclusive DIS

A. Afanasev·M. Strikman·C. Weiss
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Abstract

Inclusive DIS with unpolarized beam exhibits a subtle dependence on the transverse target spin, arising from the interference of one-photon and two-photon exchange amplitudes in the cross section. We argue that this observable probes mainly the quark helicity-flip amplitudes induced by the non-perturbative vacuum structure of QCD (spontaneous chiral symmetry breaking). This conjecture is based on (a) the absence of significant Sudakov suppression of the helicity-flip process if soft gluon emission in the quark subprocess is limited by the chiral symmetry-breaking scale mu_chiral^2 >> Lambda_QCD^2; (b) the expectation that the quark helicity-conserving twist-3 contribution is small. The normal target spin asymmetry is estimated to be of the order 10^{-4} in the kinematics of the planned Jefferson Lab Hall A experiment.

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A. Afanasev, M. Strikman, C. Weiss. 2007-09-27. Quark helicity flip and the transverse spin dependence of inclusive DIS. https://doi.org/10.1142/9789812796950_0019

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