Single-particle and collective motions from nuclear many-body correlation (PCM2025)

Coulomb Dissociation of 17B

5 Mar 2025, 15:09

1m

Main Lecture Hall (University of Aizu)

Poster session

Speaker

Hyeji Lee (Institute of Science Tokyo, University of Oslo)

Description

Neutron-rich isotopes have unique structural properties, such as the neutron halo where weakly bound neutrons are spatially extended from the core. Two-neutron halo nuclei such as ${}^6$He, ${}^{11}$Li, and ${}^{19}$B are especially interesting subject since they are Borromean nuclei. A Borromean nucleus is a bound three-body system where any of the two-body subsystems are unbound. Recent Coulomb dissociation studies of ${}^{19}$B have identified a di-neutron correlation — a compact neutron pair — in its halo[1]. We focus on ${}^{17}$B as a candidate of two-neutron halo, providing a core for ${}^{19}$B. Investigating halo properties and di-neutron correlations in ${}^{17}$B could reveal critical insights into multi-neutron halo structures. Using Coulomb dissociation experiment with the SAMURAI spectrometer at RIBF, RIKEN, a ${}^{48}$Ca primary beam at 345 MeV/nucleon was used to generate a ${}^{17}$B secondary beam via BigRIPS, followed by dissociation on a Pb target into ${}^{15}$B and two neutrons. The SAMURAI spectrometer and NEBULA neutron detector array allowed us to extract the exclusive cross section and relative energy spectrum for this dissociation. We will show the preliminary results on the $B(E1)$ spectrum of ${}^{17}$B, where we found significant soft $E1$ strength.

[1] K. J. Cook et. al., Phys. Rev. Lett. 124, 212503 (2020)