A dynamical η'-mass from an infrared enhanced gluon exchange

The pseudo-scalar flavor-singlet meson mixes with two gluons. A dimensional argument by Kogut and Susskind shows that this can screen the Goldstone pole of the chiral limit in this channel, if the gluon correlations are infrared enhanced. Using a gluon propagator as singular as σ/k4 for k2→0 we relate the screening mass to the string tension σ. In the Witten-Veneziano action to describe the η-η' mixing this relation yields masses of about 810 MeV for the η', 430MeV for the η and a mixing angle of about -30 degree from the phenomenological value σ∼0.18GeV2. The very weak temperature dependence of the string tension should make this mechanism experimentally distinguishable from exponentially temperature dependent instanton model predictions. copyright 1997 American Institute of Physics