Experimental evidence of the 6He level at E* = 18.3 MeV via the 4He + 3H three-body reaction

Measurements of the t-t and p-t coincidence events in the 3H (α, tt)1H reaction have been obtained at incident energy Eα = 67.2 MeV. Various appropriate angular configurations of detectors were chosen in order to observe the population of the 6He∗ state at around 18 MeV. Its contribution appears at the relative energy of Et t = 6.0 MeV as found from an analysis of the bidimensional spectra. We found the formation of the 6He excited state at E∗= 18.3 ± 0.2 MeV (with a width of 1.1 ± 0.3 MeV) by using the decay into the t + t binary channel, since the threshold energy of the t + t channel is 12.31 MeV. In each analyzed bidimensional energy spectrum of (Et,Et) and (Ep, Et ) coincidence events, resonance structures are present due to the formation of both 6He∗ and 4He∗ excited states. Our results on the E∗ and values regarding the 6He∗ level of about 18 MeV are compared with the results obtained using other reactions. Moreover, we also found new width values of 0.7 ± 0.3 and 0.8 ± 0.4 MeV for the 14.0 ± 0.4 and 16.1 ± 0.4 MeV 6He levels, respectively