1999/04/30 by R. Kotte, H. W. Barz, C. Plettner +3
Physics and Astronomy · #nucl-ex
published as Eur.Phys.J. A6 (1999) 185-195 · 11 pages, 12 included figures, accepted by Eur. Phys. Journ. A
arxiv created 1999/08/17 · arxiv updated 2009/12/01
Small-angle correlations of pairs of nonidentical light charged particles produced in central collisions of heavy ions in the A=100 mass region at a beam energy of 400 AMeV are investigated with the FOPI detector system at GSI Darmstadt. The difference of longitudinal correlation functions with the relative velocity parallel and anti-parallel to the center-of-mass velocity of the pair in the central source frame is studied. This method allows extracting the apparent space-time differences of the emission of the charged particles. Comparing the correlations with results of a final-state interaction model delivers quantitative estimates of these asymmetries. Time delays as short as 1 fm/c or - alternatively - source radius differences of a few tenth fm are resolved. The strong collective expansion of the participant zone introduces not only an apparent reduction of the source radius but also a modification of the emission times. After correcting for both effects a complete sequence of space-time emission points of p, d, t, 3He, alpha particles is presented for the first time.