The role of the axial anomaly in measuring spin-dependent parton distributions

R. D. Carlitz, J. C. Collins, A. H. Mueller

Research output: Contribution to journalArticle

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It is shown that forward matrix elements of j5μ, the flavor singlet axial vector current, do not merely measure the helicity carried by quarks and antiquarks but also include a spin-dependent gluonic component due to the anomaly. In perturbation theory the exact value of the gluonic component depends on the infrared regulator, and we argue that computing off-shell matrix elements with zero-mass quarks gives the proper method of regulation to exhibit the chiral properties of the theory. We suggest measuring two-jet production in deep inelastic scattering off polarized targets as a means of determining the spin-dependent gluonic component of j5μ.

Original languageEnglish (US)
Pages (from-to)229-236
Number of pages8
JournalPhysics Letters B
Issue number2
Publication statusPublished - Nov 17 1988


All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics

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