Light fragment yields from central Au plus Au collisions at 11.5A GeV/c - art. no. 044906

Inclusive double differential multiplicities of deuterons, H-3, He-3, and H e-4 measured by E877 for 11.5A GeV/c Au + Au collisions at the Brookhaven's Alternating Gradient Synchrotron (AGS) are presented. Light fragments at b eam rapidity are measured for the first time at AGS energies. Beam rapidity deuteron and He-4 yields and transverse slope parameters are found to be s trongly dependent on the impact parameter, and the shape of the deuteron sp ectra is not consistent with that expected for a simple thermal distributio n. The deuteron yields relative to proton yields are analyzed in terms of a simple coalescence model. While results indicate an increase in source siz e compared to collisions of lighter systems at the same energy, they are in consistent with a simple coalescence model reflected by a rapidity dependen ce of the coalescence parameter B-d. A new approach utilizing an expanding thermalized source combined with a coalescence code is developed for studyi ng deuteron formation in heavy-ion collisions. The strong dependence of deu teron yields on collective motion implies that deuteron yields relative to those of protons can be used for constraining source parameters.