Heavy Nuclei andαParticles between 7 and 100 Bev/Nucleon. II. Fragmentations and Meson Production

Three hundred and seventeen heavy-nuclei and 175 $\alpha$-particle interactions of more than 7 Bev/nucleon have been found in a systematic way and analyzed. We obtained average values and fluctuations of the individual values for the energy of heavy nuclei as measured by the opening angle of their fragments by comparing with the energy found by scattering measurements. At an average energy of 10 Bev/nucleon and 40 Bev/nucleon the average number of charged mesons produced by $\alpha$-particle interactions with emulsion nuclei was found to be 4.6 and 8.2, respectively. About one half of the nucleons of the $\alpha$ particle participate in the collision. The meson multiplicities per participating nucleon agree for proton and $\alpha$-particle collisions at 10 Bev/nucleon.