The Emc Spin Crisis: Comparing Proton and Photon
Abstract
The "kinematical" resolution of the $U_A(1)$ problem is proposed. The cancellation of photonic and gluonic anomalies suggested by the t'Hooft consistency principle naturally explains the zero singlet contributions to the first moments of proton and photon spin structure functions. The new sum rule for the photon spin structure function is derived. The strong strong $Q^2$dependence of the GerasimovDrellHearn sum rule is related to the $G_2$ structure function and to the gluonic anomaly.
 Publication:

arXiv eprints
 Pub Date:
 March 1993
 arXiv:
 arXiv:hepph/9303228
 Bibcode:
 1993hep.ph....3228T
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 8 pages (2 figures included into the text), LATEX, the updated contribution to XI High Energy Physics Seminar, Dubna, September 1992