Production of Hypernuclei in PANDA: Hyperon production target

The study of double Λ hypernuclei is one of the major physics programs within the program of PANDA [1, 2]. The experimental setup, as described in [3], comprises a primary nuclear target which will be hit by the antiproton beam. Double Hypernuclei are produced via the stopping and absorption of double strange baryons Ξ− in a nucleus [4]. Thus, it’s the task of the so-called primary target to produce ΞΞ pairs in a pA reaction, while the stopping, absorption and hypernucleus production takes place in a secondary target. The primary reaction takes place close to the production threshold at an p momentum of 3 GeV/c, since the produced hyperons should not be too high in energy to be stopped furtheron. The elementary reactions are p + n → Ξ 0 + Ξ− and p + p → Ξ + + Ξ−. Model studies in the framework of an Intranuclear Cascade Model (see [4]) were performed using a cross section of 2 μb, the mass number of the nucleus enters as A. The relevant quantity for the envisaged reaction is the number of stopped Ξ− with respect to the total number of produced Ξ−. This production factor depends on several parameters, namely the production rate, the distance between the primary target and the secondary target where the hyperons finally should be stopped and absorbed, the beam pipe diameter and the materials and geometry of the targets as well. The secondary target in the calculations was represented by a solid carbon block with a cylindrical hole (modelling the beam pipe).