Determination of the effective strong coupling constant αs.g1 (Q2) from CLAS spin structure function

We present a new extraction of the effective strong coupling constant alpha(s,g1) (Q(2)). The result agrees with a previous determination and extends the measurement of the low and high Q(2) behavior of alpha(s,g1) (Q(2)) that was previously deduced from sum rules. In particular, it experimentally verifies the lack of Q(2)- dependence of alpha(s,g1) (Q(2)) in the low Q(2) limit. This fact is necessary for application of the AdS/CFT correspondence to QCD calculations. We provide a parameterization of alpha(s,g1) (Q(2)) that can equivalently be used to parameterize the Q(2)-dependence of the generalized Gerasimov-Drell-Hearn and Bjorken sums. (c) 2008 Elsevier B.V. All rights reserved.