Possible measurement of P-states probability in the $^4$He nucleus

Abstract

Using the experimental data on total {\it S}=1 transition cross-sections \, for $^4$He$(γ,p)$$^3$H and $^4$He$(γ,n)$$^3$He reactions as the base, the paper describes the possibility of measuring the probability of {\it P}-states in the $^4$He nucleus. The {\it S}=1 transitions may originate from $^3P_0$ states of the nucleus, or be the result of the spin-flip of the final-state particle system from $^1S_0$, or $^5D_0$ states of the $^4$He nucleus, and also as a result of the secondary effects. The analysis of the experimental data has suggested the conclusion that within the statistical error the ratio of the {\it S}=1 transition cross-sections in the collinear geometry to reaction cross-sections at polar nucleon-exit angle $θ_N$=$90^{\circ}$ $ν_p$ and $ν_n$ in the photon energy range 22$\le$E$_γ$$\le$100 MeV is independent of the photon energy. This is in agreement with the assumption that the {\it S}=1 transitions can originate from $^3P_0$ states of the $^4$He nucleus. Average values of magnitude $ν_p$ and $ν_n$ in the mentioned photon energy range are calculated $ν_p$=0.01$\pm$0.002 and $ν_n$=0.015$\pm$0.003. The errors are statistical only.