DILEPTON PRODUCTION FROM P-P TO CA-CA AT THE BEVALAC

The DLS collaboration has recently completed a high statistics study o f dilepton production at the Bevalac. In particular, we have measured dielectrons (e(+)e(-)) from p-p and p-d collisions to understand the b asic dilepton production mechanisms in the energy range from 1.05 - 4. 9 GeV. These data can be used to determine the basic processes which c ontribute to nucleon-nucleon dilepton production such as hadronic brem sstrahlung, vector meson processes, and hadronic Dalitz decay. The dat a show that a simple elastic bremsstrahlung calculation is insufficien t to explain the data. Theoretical models are compared with the data. A new high statistics study of Ca-Ca at 1.05 A . GeV has been made to study the collectivity of A-A collisions.