Observation of Dilepton Production in Calcium - Collisions at 2.1 Gev/nucleon Kinetic Energy

This thesis was prepared under the guidance of Professor Leon Madansky. The measurement of the production rate of low mass dielectrons (0.05 < m _{e{^+}e{^-} } < 1.25 GeV/c^2) produced in Ca^{40} -Ca^{40} collisions at 2.1 GeV/nucleon kinetic energy is reported. Various candidate production mechanisms are presented. An inter-nuclear -cascade Monte-Carlo calculation which accounts for all observed dielectron production by the electromagnetic decay of known mesons (pi^0, eta and rho) and higher nucleon states, baryon bremsstrahlung and a possible contribution by pi^{+}pi^ {-} annihilation is described. We study the possibility that high mass dielectron production occurs in central Ca^{40}-Ca ^{40} collisions by performing an associated charged particle multiplicity analysis.