PROXIMAL CHIRAL PHASE-TRANSITION

We consider the form of the chiral-symmetry-breaking piece of the effe ctive potential in the linear sigma model. Surprisingly, it allows for a second local minimum at both zero and finite temperatures. Even tho ugh chiral symmetry is not exact, and therefore is not restored in a t rue phase transition at finite temperature, this second minimum can ne vertheless mimic many of the effects of a first-order phase transition . We derive a lower limit on the height of the second minimum relative to the global minimum based on cosmological considerations; this limi t is so weak as to be practically nonexistent. In high energy nuclear collisions, it may lead to observable effects in Bose-Einstein interfe rometry due to domain walls and to coherent pion emission.