# Application of an ab-initio S-matrix to data analysis of transfer to the continuum reactions populating 11Be

## TL;DR

This paper employs an ab-initio S-matrix derived from the NCSMC method to analyze transfer to the continuum reactions populating 11Be, confirming known levels and providing evidence for a new 9/2+ state at 5.8 MeV.

## Contribution

It introduces the use of the NCSMC-derived S-matrix in a Transfer-to-the-Continuum calculation for the first time, linking ab-initio nuclear structure with reaction analysis.

## Key findings

- Confirmed known 11Be levels in the spectrum.
- Provided evidence for a new 9/2+ state at 5.8 MeV.
- Validated the TC approach with experimental data.

## Abstract

Recently, the bound and continuum spectrum of 11Be has been calculated within the ab-initio no-core shell model with continuum (NCSMC) method successfully reproducing the parity inversion in the ground state. The continuum spectrum obtained is in agreement with known experimental levels. The S-matrix contained in the NCSMC continuum wave functions of the n+10Be system is used in this work for the first time in a Transfer-to-the-Continuum (TC) reaction calculation. The TC approach is applied to study the excitation energy spectrum of 11Be measured in the 9Be(18O,16O)11Be reaction at 84 MeV. Previously known levels are confirmed and theoretical and experimental evidence for a 9/2+ state at Ex=5.8 MeV is given, whose configuration is thought to be 10Be(2+)+n(d5/2).