NUCL 10

σ_EVR=Σσ_capture(Ecm,J)P_CN(Ecm,J)Wsur

where σ_capture(Ecm, J) is the capture cross section at center of mass energy Ecm and spin J and P_CN is the probability that the projectile-target system will evolve inside the fission saddle point to form a completely fused system rather than re-separating (quasifission) and Wsur is the probability that the completely fused system will de-excite by neutron emission rather than fission. For a quantitative understanding of the synthesis of new heavy nuclei, one needs to understand σ_capture, P_CN, and Wsur for the reaction system under study. The capture cross sections are relatively well understood, but predictions of the values of Wsur and P_CN differ by orders of magnitude. I describe some recent experiments that measure P_CN by characterizing the fission angular distributions in these reactions and recent experiments that measure Wsur using direct counting of the emitted neutrons in these reactions.