Breakup ofC12resonances into threeαparticles

Abstract

The reaction 3 He + 11 B → d + 12 C * has been used to populate resonances in 12 C up to an excitation energy of 15 MeV. The subsequent breakup to three α particles has been measured in complete kinematics. Dalitz plots are used to visualize and analyze the data. The Dalitz plot intensity distribution exhibits zero points characteristic of the total spin and parity of the 3α system allowing us to determine the spin and parity of a state in 12 C at 13.35 MeV whose quantum numbers were hitherto not well established. The Dalitz plot intensity distributions of the 2 − state at 11.83 MeV and the 1 + state at 12.71 MeV are compared with the predictions of a recent three-body calculation as well as with simpler models. All are able to reproduce the gross structures seen in the Dalitz plot, but none give an accurate description of the detailed profile of the distributions.

Evidence for Triangular D3h Symmetry in C12Marín-Lámbarri1, Bijker2, Freer3 et al. 2014Phys. Rev. Lett.204142442View full textAdd to dashboardCite

“…In addition, the 4 − state recently observed by some of us at 13.35 MeV in 12 C [5,6] confirms the J π = 4 ± parity doublet predicted by this U(7) model for the ground state band of 12 C.…”

Nuclear stopping and light charged particle emission in C12+C12 at 95 MeV/nucleon

“…The energy spectra shown in Fig. 7 indicate that this difference originates from the exhibition of the alpha cluster structure in 12 C nuclei when they are excited below 10-15MeV [44,45]. In our analysis, the P 0 values for 4 He and deuterons show a similar value for the IV component, which is distinct contract to those of other analysis, such as those of 40 Ar + 112 Sn at 47 MeV/nucleon [46] and 16 O + 197 Au at 310 MeV/nucleon [7].…”

Three-body bremsstrahlung and the rotational character of theC12spectrum

“…Together with the 0 + and 2 + states mentioned above, a 4 + resonance is known to be at an excitation energy of 14.1 MeV [4,6]. Other 4 + states have also been obtained numerically.…”

“…Its properties have recently been thoroughly reviewed [3]. Since then, many other resonant states have been observed in 12 C [4][5][6][7][8][9]. Among them, one of the most elusive ones has been the second 2 + 2 state, which was predicted by different theoretical methods to have an excitation energy of around 10 MeV [10][11][12].…”