Formation of double-Λ hypernuclei at PANDA

Abstract

We study the formation of single-and double-Λ hypernuclei in antiproton-induced reactions relevant for the forthcoming PANDA experiment at FAIR. We use the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model with relativistic mean-fields for the description of non-equilibrium dynamics and the statistical multifragmentation model (SMM) for fragment formation. This combined approach describes the dynamical properties of strangeness and fragments in low energypinduced reactions fairly well. We then focus on the formation of double-Λ hypernuclei in high energyp-nucleus collisions on a primary target including the complementary Ξ-induced reactions to a secondary one, as proposed by the PANDA Collaboration. Our results show that a copious production of double-Λ hyperfragments is possible at PANDA. In particular, we provide first theoretical estimations on the double-Λ production cross section, which strongly rises with decreasing energy of the secondary Ξ-beam.

Production and Interactions of Hyperons and Hypernuclei

“…On the theory side, major activities in this direction are being made by the Frankfurt-Mainz collaboration [29,30] and our own investigations. In a series of paper [24][25][26][27][28] we have been studying hyperon and hypernuclear production in proton and antiproton-induced reaction and in heavy ion collisions leading to fragmentation into light hypernuclei. In [28] we have for the first time investigated the role and possible observable effects of different YN-interaction models on the strangeness dynamics of hadron-induced reactions.…”

Particle production in antiproton-induced nuclear reactions

“…Strangeness production and formation of hypernuclei in antiproton induced nuclear reactions has been investigated throughly with the Giessen Boltzmann-Uehling-Uhlenbeck (GiBUU) transport model [2,3]. The production of hypernuclei is associated with the reaction channels of hyperons and also hyperon-nucleon (HN) potential.…”

In-medium effects on hypernuclear formation

“…Recently, we have studied the formation of S = −1 and S = −2 hypernuclei in various reactions [3] within a covariant transport model [4]. Here we focus on the discussion of the production mechanisms of double-Λ hypernuclei at PANDA.…”

“…The investigation of hypernuclei can provide information also on the still less known hyperon-nucleon and hyperon-hyperon interactions. For the latter the production of double-Λ hypernuclei is important, which is one of the main projects of the PANDA Collaboration [2].Recently, we have studied the formation of S = −1 and S = −2 hypernuclei in various reactions [3] within a covariant transport model [4]. Here we focus on the discussion of the production mechanisms of double-Λ hypernuclei at PANDA.…”

“…The meson-nucleon coupling constants g i (i = σ, ω, ρ) and also the additional parameters of the non-linear self-interactions of the σ meson (not shown here) are taken from the widely used NL parametrizations, see [3] for details. The antinucleon-meson coupling constants are rescaled by a phenomenological constant such, to reproduce data in high-energy antiproton-induced reactions [3].…”