V.I. Petrukhin

Large-angle quasi-free scattering in 6Li(p, pd)4He at 670 MeV

Abstract The 6 Li(p, pd) 4 He reaction was investigated at 670 MeV by a coincidence experiment with a large-angle scattering geometry. The energy sharing and angular correlation of the reaction products were measured and the momentum distribution of the recoil nucleus was determined for transitions leading to residual nuclei in the ground and excited states. Results were analysed in terms of a simplified distorted-wave impulse approximation using cluster-model and three-body wave functions. The observed momentum distribution of the p-n pair in the p-shell of 6 Li is in agreement with three-body calculations, while the spectroscopic factor is larger than predicted by theory. Transitions to breakup states of the α-particle also have the characteristics of quasi-free scattering on deuteron clusters.

Study of the spectra of fast deuterons produced in the interaction of 670 MeV protons with nuclei

Abstract The spectra of deuterons emitted at angles of 6.5°, 9.5°, 13.5° and 16° (lab system) in the interaction of protons with the nuclei 1 H, 2 H, 6 Li, 7 Li, C, Al, Cu, Rh and Pb have been measured in the momentum range 700–1700 MeV/ c . The secondary particles were analyzed with the help of magnetic and time-of-flight spectrometers. The differential cross sections for deuteron production in the reactions p + 〈2N〉 → N + d and p + 〈N〉 → d + π have been measured for selected nuclei and angles. The effective numbers of nucleons and of two-nucleon clusters for the investigated nuclei were determined. The results obtained are discussed in terms of the dispersion theory of direct nuclear reactions.

Radiative capture of stopped negative pions by nuclei

Abstract Experiments aiming at the radiative capture of stopped π − mesons by nuclei are described. The probability of the process detected is 2 · 10 −2 and depends weakly upon nuclear charge and mass. The energy spectrum of γ -quanta emitted in the capture turned out to be “hard”. The mean γ -energy was about 80 MeV.

On the charge exchange of stopped negative pions on complex nuclei

Abstract It is shown that stopped π−-meson charge exchange on complex nuclei is sharply suppressed.

Studies on the atomic capture of stopped negative pions in binary mixtures of 3He with other gases

Abstract Systematic experimental study has been carried out on the atomic capture of negative pions by 3He in binary gas mixtures of 3He + Z, where Z is Ne, Ar, Kr, Xe, N2, O2, CO2 and sf6. The results are analysed in the framework of a phenomenological model. It is shown that there is no pion transfer from the 3 H eπ − mesic atoms to the heavier Z-atoms. The probabilities of pion capture in the various atoms of the mixtures are found to be proportional to the atomic concentrations, thereby excluding the possibility of a concentration dependence in the atomic capture ratio A(Z/3He). In contradiction to previous assumptions the probability of pion capture into an atomic orbit is not proportional to the stopping power of the components of the mixture. The atomic capture ratio of pions in a 3He + 4He mixture is A( 4 He / 3 He ) = 0.75 ± 0.13 , which might be the indication of an isotopic effect. The branching ratio for the charge-exchange reaction at rest (π − + 3 He → π 0 + 3 H ) is found to be 0.128 ± 0.012.

Quasi-free scattering in 7(p, pd)5He and 12C(p, pd)10B reactions at 670 MeV

Abstract The reactions 7 Li(p, pd) 5 He and 12 C(p, pd) 10 were investigated at 670 MeV in quasi-free scattering geometry at large angles. In transitions to low-lying as well as to highly excited states of the residual nuclei the energy distributions of the scattered protons are in agreement with the mechanism of quasi-free scattering on quasi-deuterons in the p- and s-shells of 7 Li and 12 C.

Charged particle multiplicities in π−1,K− and\(\bar p\) interactions with nuclei at 40 GeV/c

AbstractInteractions of 40 GeV/c πp-,K− and

Neutral strange particle production in high transverse momentum π− nucleus interactions at ∼40 GeV/c

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