Three α-particle decay of C12

Complete kinematical study of the 3 $\alpha$ breakup of the 16.11 MeV state in 12C

“…In the 1960s and 1970s it was demonstrated that the breakup primarily proceeds in a sequential manner, i.e., 12 C → α 1 + 8 Be followed by 8 Be → α 2 + α 3 . The sequential model was successfully applied to describe the breakup of several states in 12 C [2], but it failed in the case of the (J π , T ) = (2 + , 1) state at an excitation energy of 16.11 MeV. Initially, this led to the suggestion that the breakup of the 16.11 MeV state proceeds directly to the 3α final state [3], but it was later shown that the breakup can be described within a more sophisticated sequential model, which takes into account the interference due to Bose symmetry in the 3α final state [4][5][6][7][8].…”

R-matrix description of particle energy spectra produced by low-energyH3+H3Brune1, Caggiano2, Sayre3 et al. 2015Phys. Rev. C230360View full textAdd to dashboardCite

“…The functions W (i) lJl J are real and are invariant under the interchange of (l, J) and (l , J ), while W (12) lJl J are also real and are invariant under the interchange of (l, J) and (l , J ) and particle labels 1 and 2. These functions are tabulated in Table I for the partial wave combinations considered here.…”

“…The g (12) term arises from treating the neutron as indistinguishable fermions. In the case of neutron emission via intermediate 5 He states, we take neutron 1 to the first neutron emitted and neutron 2 to be the second.…”

“…The nature of the energy dependence of u c varies with the channel type (nα versus nn); the 12 and 21 notation is used to indicate direct (12) and exchange (21) terms. In principle, all observables can now be calculated.…”

“…where the product of factors p i p jk J ijk is the three-body phase space [2,12], and J ijk is the Jacobian for the transformation from the (…”