Two-kaon And Two-proton Interferometry In 158 Gev/nucleon Lead + Lead Collisions

Kaon and proton interferometry measurements are made for the reactions Pb + Pb &rarr; K<super>+</super>K<super>+</super> + X and Pb + Pb &rarr; pp + X using the 158 GeV/nucleon <super>208</super>Pb beam from the CERN Super Proton Synchrotron (SPS). Two-particle intensity interferometry measurements are sensitive to the spatial and temporal extent of the source as well as the expansion dynamics of the system. The focussing spectrometer experiment NA44 is used to detect the position and momentum coordinates of kaons and protons. NA44 has a narrow experimental acceptance that lies near mid-rapidity; for these measurements, the 131 mr angular setting was used, with a mean transverse momentum of 910 MeV/c. Two-particle Coulomb corrections and experimental acceptance corrections are applied to the kaon data, which are fit to one- and two-dimensional Gaussian functions in momentum space to obtain radius parameters. Because proton correlations cannot be fit to analytic functions, different methods are used to extract radius parameters from the proton data.