The distributions of residual nuclei after annihilation of stopped antiprotons in 92M0, 95M0, 98M0 and 165H0 targets have been measured by means of the induced radioactivity. In the case of the 165H0 target the residual nucleus ~ 16Te was observed thus indicating that about 50 nucleons may be emitted after annihilation. The distributions have also been calculated with two versions of an intranuclear cascade model. The agreement between theory and experiment is satisfactory. The effects of heavy mesons in the annihilation process, of local reduction of the nuclear density during the intranuclear cascade and of multifragmentation are discussed.

Antiprotons have been stopped in a target of Ba(NO3) 2 . The induced radioactivity from antiproton annihilation in Ba was used to determine the distribution of residual nuclei. The results are compared with intranuclear cascade calculations. The agreement between theory and experiment is very good.

Gamma rays and, for the first time, conversion muons of pt fusion have been measured from liquid mixtures of protium, deuterium, and tritium. The rate Aio for spin flip from the triplet to the singlet state of t/i(ls) was found to be Aio = (1.06 ± 0.13) x 10^/xs~^, the rate for muon-catalyzed pt fusion from the (/ = 1) nuclear-spin state to be X{,t{I = I) = 0.067 ± 0.002 Ig;^^! Ms"\ and the molecular formation rate to be A^ = (7.5 d= 0.3 to.s) Ms"-^ (all rates normalized to liquid hydrogen density).

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Antiprotonic x-ray spectra of 92 Mo, 94 Mo, 95 Mo, 98 Mo, and 100 Mo have been measured with Ge detectors. The £2 nuclear-resonance effect was observed for the first time in p atoms, yielding information on the "hidden" n -5, / = 4 level of the ^-molybdenum atom. Strong interaction widths and shifts affecting the 7-6 transition were determined and the effective p-nucleon scattering length was deduced. A unique strong-coupling effect was established in ]> 100 Mo. PACS numbers: 36.10.-k, 13.75.Cs, 23.20.QzAntiprotonic atoms are successfully used to obtain information on the strong interaction between matter and antimatter at low energies. The strong interaction leads to a shift and to a broadening of the ^-atomic levels compared with the values calculated without strong interaction. These effects are best observed in the last antiprotonic transition which can be seen. The data are usually interpreted in terms of phenomenological ^-nucleus or p-nucleon optical potentials and scattering lengths 1 ; however, microscopic models 2 have been recently constructed.An additional source of information on the antiproton-nucleus interaction is provided by the hadronic E2 nuclear-resonance effect, 3 which has previously been observed in pionic 4 and kaonic 5 atoms. This effect occurs when an atomic deexcitation energy matches a nuclear excitation energy and the electric quadrupole coupling induces configuration mixing. For />-94 Mo and p-l00 Mo this effect was predicted some years ago. 3 The relevant levels for both isotopes are shown in Fig. 1.In the case of 94 Mo the spacing between the antiprotonic (»,/) = (7,6) and (5,4) levels (844.8 keV) is sufficiently close to the first F = 2+ nuclear excitation energy (871.1 keV) to allow configuration mixing of the (7,6;/ 1P «0 + ) and (5,4;/ ir -2 + ) states. The ad-2 + 871.1 keV 210.2keV 144.0keV^n = 9, 1 = 8 r ^W n=8, 1 = 7 n = 7, 1 = 6 324.1 keV /' \ n = 6, t = 5 520.7 keV 0* 0.0 keV £_ n = 5, 1 = 4 0* 0.0 keV nuclear absorption nuclear levels in 94 Mo antiprotonic levels in Mo nuclear levels ;« 100 M" FIG. 1. Nuclear and p-atomic levels in 94 Mo and 100 Mo relevant to the E2 resonance effect. 2368