Flavor singlet axial coupling of the proton — an updated analysis☆

Abstract We present a combined analysis of SESAM and T χ L data for the flavor singlet axial coupling GA1 of the proton, which is very helpful to stabilize the disconnected signals at small quark masses. From connected and disconnected contributions we use the tadpole improved renormalization constant ZA and obtain GA1 = 0.21(12).