Observation of Partial U_A(1) Restoration from Two-Pion Bose-Einstein   Correlations
  The effective intercept parameter of the two-pion Bose-Einstein correlation function, lambda_*, is found to be sensitive to the partial restoration of U_A(1) symmetry in ultra-relativistic nuclear collisions. An increase in the yield of the eta' meson, proposed earlier as a signal of partial U_A(1) restoration, is shown to create a ``hole'' in the low p_t region of lambda_*. A comparison with NA44 data from central S+Pb collisions at 200 AGeV is made and implications for future heavy ion experiments are discussed. 
Stephen E. Vance (1), Tamas Csorgo (1 and 2) and Dmitri Kharzeev (3)   ((1) Columbia Univ., (2) MTA KFKI RMKI, (3) RIKEN-BNL)