Arbeitsgruppe Alexandre Obertelli
Exotische, Seltsame und Anti-Materie


Overview of (the few) Λ-hypernuclei synthesized as of 2005. Figure from O. Hashimoto and H. Tamura, Prog. Part. Nucl. Phys. 57, 564 (2006).

Hyperons, baryons with at least one strange quark, are expected to be an important building block of high-density matter such as neutron stars. The Λ particle with quark constituents usd is the lightest hyperon, with mass 1115 MeV/c2, zero charge, isospin T = 0 and strangeness S = -1, a new quantum number not contained normally inside nuclei. The Λ hyperon is unstable and decays with lifetime 263(2) ps, typical of the weak interaction. Since strangeness is conserved in the strong interaction, the Λ particle can stay in contact with nucleons inside nuclei and form short-lived hypernuclei. The study of hypernuclei is rather recent and offer great new opportunities related to 3-body forces, the understanding of the interaction of strange particles with other hadrons and fission. Hypernuclei studies shed a new light on the world of traditional nuclei by revealing new symmetries and new phenomena.

Few hypernuclei have been synthesised and studies so far. We are interested in understanding their production from heavy-ion collisions as first pioneered by the HyPHI project at GSI [1], in view of developing a new physics program at GSI/FAIR in collaboration with other institutes interested in these studies. This implies the design and development of a new setup for hypernuclei studies. At a first stage, we focus on hydrogen induced reactions for exclusive measurements [2].

The program includes the participation to experiments on hypernuclei at the FRS.

[1] T.R. Saito et al., Nucl. Phys. A 881, 218 (2012).

[2] Y. Sun et al., arXiv:1712.04658 [nucl-th], submitted for publication (2017).