摘要: The relationship between the helicities carried by quark and gluon ofthe proton and the triangle anomaly is discussed in terms of theperturbative QCD. A new flavorindependent axial-vector current is derivedin terms of the background field theory. Using this current the quark spincontents are computed and are consistent with data. The order of magnitudeof the quark spin content is determined to be O(1)in large N(?) expansion