Proton spin structure and the axial U(1) problem
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چکیده
and the large mass of the η meson point to large violations of OZI in the flavour-singlet J = 1 channel [2–4]. The strong (QCD) axial anomaly is central to theoretical explanations of the small value of g (0) A |pDIS (about 50% of the OZI value 0.6) and the large η mass. In this paper we review the role of the anomaly in the spin structure of the proton and highlight the interplay between the proton’s internal spin structure and axial U(1) dynamics. In the QCD parton model the proton’s flavoursinglet axial charge g (0) A receives contributions from the amount of spin carried by quark and gluon partons [5,6] and from gluon topology [2], viz.
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تاریخ انتشار 2001