BOSE-EINSTEIN CORRELATIONS OF PION WAVEPACKETS

A wavepacket model for a system of free pions, which takes into accoun t the full permutation symmetry of the wavefunction and which is suita ble for any phase space parametrization is developed. The properties o f the resulting mixed ensembles and the two-particle correlation funct ion are discussed. A physical interpretation of the chaoticity lambda as localization of the pions in the source is presented. Two technique s to generate test-particles, which satisfy the probability densities of the wavepacket state, are studied: 1. A Monte Carlo procedure in mo mentum space based on the standard Metropolis technique. 2. A molecula r dynamic procedure using Bohm's quantum theory of motion. In order to reduce the numerical complexity, the separation of the wavefunction i nto momentum space clusters is discussed. In this context the influenc e of an unauthorized factorization of the state, i. e. the omission of interference terms, is investigated. It is shown that the correlation radius remains almost uneffected, but the chaoticity parameter decrea ses substantially. A similar effect is observed in systems with high m ultiplicities, where the omission of higher order corrections in the a nalysis of two-particle correlations causes a reduction of the chaotic ity and the radius. The approximative treatment of the Coulomb interac tion between pions and the source is investigated. The results suggest that Coulomb effects on the correlation radii are not symmetric for p ion pairs of different charges. For (pi(-), pi(-)) pairs the radius, i ntegrated over the whole momentum spectrum, increases substantially, w hile for (pi(+), pi(+)) pairs the radius remains almost unchanged.