Light-cone divergence in twist-3 correlation functions

Abstract

It is argued that the definition of the twist-3 transverse momentum dependent correlation functions must be modified if they contain light-like Wilson lines. In the framework of a simple spectator model of the nucleon we show explicitly the presence of a light-cone divergence for a specific twist-3 time-reversal odd parton density. This divergence emerges for all eight twist-3 T-odd correlators and appears also in the case of a quark target in perturbative QCD. The divergence can be removed by using non-light-like Wilson lines. Based on our results we argue that currently there exists no established factorization formula for transverse momentum dependent twist-3 observables in semi-inclusive DIS and related processes.

6 pages, 1 figure, slightly extended version, to appear in Phys. Lett. B

References in corpus (3)

• What exactly is a parton density?
• Collins effect in semi-inclusive deeply inelastic scattering and in electron positron annihilation
• Single-Spin Beam Asymmetry in Semi-Exclusive Deep-Inelastic Electroproduction

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