Extracting source parameters from gaussian fits to two-particle correlations

摘要

By using a general quadratic saddle-point approximation, we develop a model-independent formalism for extracting information about azimuthally symmetric sources from gaussian fits to two-particle correlation data. To use this technique, the average energy of the particle pair in the measurement frame must be less than some upper limit, which for heavy-ion collisions at the AGS or SPS is about 560 MeV. In addition to discussing the standard fitting procedure, we introduce a new gaussian fitting procedure which is an azimuthally symmetric generalization of the Yano-Koonin formalism for spherically symmetric sources. This new fitting procedure has the advantage that in addition to being able to measure source parameters in a fixed frame or the LCMS, it can also measure these parameters in the local rest frame of the source.