p p and pi pi intensity interferometry in collisions of Ar _s16 KCl at 1.76A-GeV

Abstract

Results on pp, I (_s16)I (_s16), and I (-_s14)I (-_s14) intensity interferometry are reported for collisions of Ar_s16KCl at 1.76A GeV beam energy, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18/GSI. The experimental correlation functi ons as a function of the relative momentum are compared to model calculations allowing the determination of the space-time extent of the corresponding emission sources. The I I source radii are found significantly larger than the pp emission radius. The present radii do well complement the beam-energy dependences of Gaussian source radii of the collision system of size A _s16 A 40 _s16 40 . The pp source radius at fixed beam energy is found to increase linearly with the cube root of the number of participan ts. From this trend, a lower limit of the pp correlation radius is deduced.