Discriminating between effective theories of U_{A}(1) symmetry breaking

Abstract

We address the question if one can empirically distinguish between the two proposed solutions to the ``$U_A(1)$ problem'': the 't Hooft, and the Veneziano-Witten $U_A(1)$ symmetry breaking effective interactions. Two hadronic observables are offered as discriminants: (1) The scalar ($0^{+}$) meson spectrum; (2) Weinberg's second spectral sum rule. Their present experimental status is discussed.

Comments: 6 pages, 1 eps file, Yonsei "Hadrons and Nuclei" conference proceedings