Quantum Mechanical Localization Effects for Bose-Einstein Correlations

For a set of N identical massive boson wavepackets with optimal initial quantum mechanical localization, we derive the Hanbury-Brown/Twiss (HBT) two-particle correlation function. Our result provides finite multiplicity corrections to the coherent state formalism and allows to trace back an error in the so-called cos-prescription. It suggests that what the HBT radius parameters in very small boson emitting systems (e.g. Z0-decays, p-p̄ annihilation) measure is essentially the initial spatial wavepacket width σ. Both oneand two-particle spectra depend explicitly on this width σ. Our derivation gives an algorithm for calculating one-particle spectra and two-particle correlations from an arbitrary phase space occupation (qi,pi, ti)i=1,N as e.g. returned by event generators of heavy ion collisions.