Probing UA(1) Restoration with Domain-Wall Fermions

We demonstrate a connection between UA(1)-breaking and topology. We do this by showing that UA(1) is broken in a finite volume by configurations with a nonzero topological charge Qtop. As the temperature is increased, the number of such configurations (and hence the breaking) decreases, though it is still nonzero at the highest temperature (T=1.25Tc) that we study. The question as to whether these contributions survive in the thermodynamic as well as chiral limits is still an open one.