Groundstate proton radioactivity of nuclei in the tin region

Proton radioactivities with decay energies of (0.98±0.08) MeV and (0.83±0.08) MeV were produced by the fusion reactions⁵⁸Ni+⁵⁸Ni→¹¹⁶Ba {star operator} and⁵⁸Ni+⁵⁴Fe→¹¹²Xe {star operator}, and their halflives were measured to be (33±7) μs and (109±17) μs, respectively. The intensities of the lines correspond to production cross sections of about 30 μb and 40 μb. The two activities are assigned to the direct proton decay of¹¹³Cs and¹⁰⁹I. The measured halflives are compared with values calculated for d_5/2 and g_7/2 groundstates of¹⁰⁹I and¹¹³Cs and spectroscopic factors are deduced for the decays. An extensive search for the proton decay of¹⁰⁵Sb, produced in the reaction⁵⁰Cr(⁵⁸Ni, p2n)¹⁰⁵Sb, had a negative result, excluding decay energies between 0.5 MeV and 1.5 MeV for halflives between 10 ns and 5 s.