Survival of excited, heavy compound nuclei

A number of recent searches for new elements with atomic numbers 119 and 120 by major laboratories worldwide have not reported any decay chains that are widely accepted in the community. This has led to a discussion of the factors that influence the survival of excited, heavy compound nuclei. The Cyclotron Institute at Texas A&M University has a longstanding program to study the factors that influence survival, and a number of experiments to produce nearly spherical compound nuclei near ²⁰⁸Pb have been conducted. These experiments demonstrate the critical role of the difference in the neutron binding energy and the fission barrier in determining the final reaction cross section. This talk will discuss these experiments and the newest results on excitation functions measured in the ⁴⁴Ca + ^{154,156,157,160}Gd and ⁴⁸Ti + ^158,160Gd reactions. The latter reactions also allow for the investigation of the role of deformation on survival. This talk will also discuss upgrades to the maximum magnetic rigidity and the data acquisition electronics of the AGGIE gas-filled separator, and future plans.