The fragment coalescence model

The extraction of source radii from heavy-ion collisions using coalescence models is explored. A new prescription is presented which considers nucleosynthesis via the coalescence of fragments which is, in particular, more appropriate for intermediate-energy collisions than the previous nucleon coalescence prescriptions. This fragment coalescence model provides an avenue for viewing the breakup stage of heavy-ion reactions that yields valuable complimentary information to two-nucleon and two-fragment correlation measurements. This model was applied to recent experimental data on central 55 and 115 MeV/nucleon Ar40+45Sc collisions studied at midrapidity. Source radii are presented versus the transverse velocity for six different coalescence channels leading to charge one, two, and three fragments. Particular attention is paid to the temperature input in the model, as the extracted radii depend significantly on this parameter. A means of extracting the temperature from experimental data using the present model is described. Comparisons to the two temperature-dependent nucleon coalescence models will also be discussed.