Speaker
Description
The ratio [1,2] is a new reaction observable suggested to extract accurately structural information on halo nuclei. It is based on the Recoil Excitation Breakup (REB) model [3], which predicts that taking the ratio of angular distributions for breakup and scattering, the uncertainty related to the reaction dynamics is strongly reduced [1,2]. It exhibits a much better accuracy than traditional methods, such as Coulomb breakup. We present here the first experimental test of the method for the $^{11}$Be + $^{12}$C collision at Elab=20 MeV/u. The experiment was performed at Texas A&M University cyclotron. Angular differential cross sections for scattering and inclusive one-neutron breakup cross sections have been measured with the new Si + phoswich detector array, BlueSTEAl [4], at θcm =$10^\circ$–$30^\circ$. The ratio of the inclusive breakup to elastic cross sections is, as predicted, very smooth and independent of the projectile-target interaction. This demonstrates the validity of the new method. We have extended our analysis to $^{11}$Be + $^{208}$Pb data [5], confirming that the method works well both for nuclear- and Coulomb-dominated reactions. This augurs well for our plan to extract accurate structure information of further exotic halo nuclei at FRIB.
References:
[1] P. Capel, R. C. Johnson, and F. M. Nunes, Phys. Rev. Lett. B705, 112 (2011).
[2] P. Capel, R. C. Johnson, and F. M. Nunes, Phys. Rev. C 88, 044602 (2013).
[3] R. C. Johnson, J. S. Al-Khalili, and J. A. Tostevin, Phys. Rev. Lett. 79, 2771 (1997).
[4] S. Ota et al., Nucl. Instr. Meth. A 1059, 168946 (2023).
[5] F. F. Duan et al., Phys. Rev. C 105, 034602 (2022).
| Email Address | pcapel@uni-mainz.de |
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