# Junior Researcher Webinar

Monday, 13/06 (16h, CET)
Study of the two-neutron decay of 13Li via the invariant mass method with SAMURAI@RIBF
Paul ANDRE (PhD Student at CEA-Saclay)

13Li is a neutron-rich unbound nucleus that decays into the halo nucleus 11Li via the emission of two neutrons. Studying such a system can lead to a better understanding of neutron-neutron correlations in the atomic nucleus. This study has been performed using the SAMURAI facility [1] at RIBF, RIKEN, Japan, with a high-intensity beam and a setup with large acceptance, allowing a better resolution and efficiency than achieved in past measurements at GSI [2] and NSCL [3].

A beam of 14Be impinges on the liquid hydrogen MINOS target [4], producing the 13Li isotopes via a (p,2p) reaction. The vertex of interaction is then reconstructed thanks to the tracking system around the target. The two decay neutrons are detected in the NEBULA array, and the remaining 11Li is detected in a hodoscope [5]. Thanks to the reconstruction of the momenta of all the decay products with the aforementioned detectors, the invariant masses of the 11Li-n-n system, the 11Li-n system and the n-n system are computed. With this quantity, more information on the spectroscopy of 13Li, such as the energy of the neutron resonances, can be provided. Using correlation plots of the Jacobi coordinates of the system [6], information on the nature of the decay (e.g. sequential or direct) can also be deduced.

References :
[1] T. Nakamura, Y. Kondo, Nucl. Instrum. Methods Phys. Res. B 376 (2016) 156-161
[2] Yu. Aksyutina et al., Phys. Lett. B 666 (2008) 430-434
[3] Z. Kohley et al., Phys. Rev. C 87 (2013) 011304(R)
[4] A. Obertelli et al., Eur. Phys. J A 50 (2014)
[5] T. Kobayashi et al., Nucl. Instrum. Methods Phys. Res. B 317 (2013) 294-304
[6] R.J. Charity et al., Phys. Rev. C 84 (2011) 014320

Organizers
Q. Fable (L2IT-IN2P3 Toulouse) – quentin.fable@l2it.in2p3.fr,
M. Forge (IPHC-CNRS Strasbourg) – mforge@iphc.cnrs.fr,
A. Revel (IRFU-CEA Saclay) – aldric.revel@cea.fr.