Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C

Details Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C

2010-11-29

arxiv.org/abs/1011.6128v1

Phys.Lett.B695:469-475,2011

Physics

Nuclear Physics

Nuclear Theory

Accepted for publication in Phys. Lett. B

Scientific paper

10.1016/j.physletb.2010.11.061

While the Hoyle state (the isoscalar $0^+_2$ excitation at 7.65 MeV in $^{12}$C) has been observed in almost all the electron and $\alpha$ inelastic scattering experiments, the second $2^+$ excited state of $^{12}$C at $E_{\rm x}\approx 10$ MeV, believed to be an excitation of the Hoyle state, has not been clearly observed in these measurements excepting the high-precision \aap experiments at $E_\alpha=240$ and 386 MeV. Given the (spin and isospin zero) $\alpha$-particle as a good probe for the nuclear isoscalar excitations, it remains a puzzle why the peak of the $2^+_2$ state could not be clearly identified in the measured \aap spectra. To investigate this effect, we have performed a microscopic folding model analysis of the \ac scattering data at 240 and 386 MeV in both the Distorted Wave Born Approximation (DWBA) and coupled-channel (CC) formalism, using the nuclear transition densities given by the antisymmetrized molecular dynamics (AMD) approach and a complex CDM3Y6 density dependent interaction. Although AMD predicts a very weak transition strength for the direct $(0^+_1\to 2^+_2)$ excitation, our detailed analysis has shown evidence that a weak \emph{ghost} of the $2^+_2$ state could be identified in the 240 MeV \aap data for the $0^+_3$ state at 10.3 MeV, when the CC effects by the indirect excitation of the $2^+_2$ state are taken into account. Based on the same AMD structure input and preliminary \aap data at 386 MeV, we have estimated relative contributions from the $2^+_2$ and $0^+_3$ states to the excitation of $^{12}$C at $E_{\rm x}\approx 10$ MeV as well as possible contamination by $3^-_1$ state.

Affiliated with

Also associated with

No associations

Rating

Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hindrance of the excitation of the Hoyle state and the ghost of the $2^+_2$ state in $^{12}$C will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-220314