A global study of $^9$Be + p at 2.72 A MeV

TL;DR

This study investigates the breakup decay rate of $^9$Be+p at 2.72A MeV using a full kinematic experimental approach and compares it with higher energy data at 5.67A MeV through a 4-body CDCC model, highlighting continuum couplings.

Contribution

It provides the first detailed experimental measurement at 2.72A MeV and compares it with higher energy data using advanced theoretical modeling, validating the 3-body structure model of $^9$Be.

Findings

Strong coupling to continuum at 2.72A MeV confirmed by elastic scattering data.

Good agreement between experimental breakup cross sections and CDCC calculations.

Validation of the 3-body model for $^9$Be structure and reaction rates.

Abstract

Background: In our recent experiment, $^9$Be+p at 5.67A MeV, the breakup decay rates to the 3 configurations, $\alpha$+$\alpha$+n, $^8$Be$^*$+n and $^5$He+$^4$He of $^9$Be, were observed and quantified, in a full kinematics approach. Unfolding step by step the accessibility to the above configurations, it will require similar studies at lower and higher energies as well as the interpretation of the data in a theoretical framework. Purpose: Investigate the breakup decay rate of $^9$Be+p at 2.72A MeV, where the $\alpha$+$\alpha$+n configuration is mainly accessible. Compare and interpret data at 2.72A MeV and 5.67A MeV into a 4-body CDCC formalism; Point out and discuss couplings to continuum. Methods: Our experimental method includes an exclusive breakup measurement in a full kinematic approach of $^9$Be incident on a proton target at 2.72A MeV, together with elastic scattering and other reaction channels measurements under the same experimental conditions. The interpretation of the data at 2.72A MeV and 5.67A MeV is considered in a 4-body CDCC approach, using the Transformed Harmonic Oscillator method for the 3-body projectile. Results: An elastic scattering angular distribution at 2.72A MeV is measured, which compares very well with CDCC calculations, indicating a strong coupling to continuum. At the same energy, the measured breakup and total reaction cross sections present good agreement with the calculated values. Further on, the elastic scattering and breakup cross section data at 5.67A MeV are found in very good agreement with the CDCC calculations. The present results support further our 3-body model for the structure of $^9$Be, validating relevant radiative reaction rates obtained previously.