Speaker
Tatiana Leonova
(NRNU MEPhI)
Description
The ground state of the heavy helium isotope $^{8}$He (J$^{P}$ = 0$^{+}$ ) has the highest ratio of number of neutrons to protons N/Z = 3 among nucleon-stable nuclear states. Excited levels $^{8}$He were observed in several experiments, however, statistics of the results is low.
In present work, studies of the level structure of $^{8}$He have been performed in the reaction of stopped pion absorption by $^{9}$Be nuclei. The experiment was carried out at the LAMPF meson factory with a two-arm semiconductor spectrometer of charged particles. The formation of the $^{8}$He was observed in the missing mass spectrum of the reaction $^{9}$Be ($\pi^{-}$, d)X. The advantage of inclusive approach is a high energy resolution (FWHM = 0.4 MeV) in comparison with correlation measurements. The missing mass spectrum in the range (0, 10 MeV) has been described using the superposition of distributions on the phase volumes and the three states of $^{8}$He with the following parameters (Ex, G): (0.1$\times$0.1 MeV, 0.1$\times$0.1 MeV), (3.8$\times$0.2 MeV, 0.3$\times$0.1 MeV) and (4.6$\times$0.3 MeV, 0.3$\times$0.1 MeV). These results have been compared with data of other experimental and theoretical works.
Primary author
Tatiana Leonova
(NRNU MEPhI)
Co-authors
Dr.
Boris Chernyshev
(National Research Nuclear University MEPhI)
Sergei Lapushkin
(NRNU "MEPhI")
Dr.
Yuri Gurov
(NRNU "MEPhI")