Disoriented Chiral Condensates and Anomalous Production of Pions

Abstract

The leading-particle effect and the factorization property of the scattering amplitude in the impact parameter space are used to study semiclassical production of pions in the central region. The mechanism is related to the isospin-uniform solution of the nonlinear $ σ$-model coupled to quark degrees of freedom. The multipion exchange potential between two quarks is derived. It is shown thatthe soft chiral pion bremsstralung also leads to anomalously large fluctuations in the ratio of neutral to charged pions. We show that only direct production ofpions in the form of an isoscalar coherent pulse without isovector pairs can lead to large neutral-charged fluctuations.