PROTON SPIN CONTENT - LINKS TO QCD TOPOLOGICAL SUSCEPTIBILITY

The part of the proton spill C carried by u, d, s quarks is calculated in the framework of the QCD sum rules in the external fields. The ope rators up to dimension 9 are accounted. An important contribution come s from the operator of dimension 3, which in the limit of massless u, d, s quarks is equal to the derivative of QCD topological susceptibili ty chi'(0) The comparison with the experimental data on Sigma gives ch i'(0) = (2.3 +/- 0.6) x 10(-3) GeV2. The limits on Sigma and chi'(0) a re found from selfconsistency of the sum rule,Sigma greater than or eq ual to 0.05, chi'(0) greater than or equal to 1.6 x 10(-3) GeV2. The v alues of g(A) = 1.37 +/- 0.10 and g(A)(8) = 0.05 +/- 0.15 are also det ermined.