Study of the Λ(1116) interaction in cold nuclear matter

Oliver Arnold

doi:10.1051/epjconf/20146609002

Abstract

The interaction of Λ hyperons with baryonic nuclear matter at saturation density is expected to be attractive. The interaction strength was extracted from hypernuclei data. A different approach to obtain the potential depth of the Λ mean-field potential is to compare experimental data with transport simulations. We analyze experimental data of Λ hyperons measured with the HADES detector in p+93 Nb reactions with a kinetic beam energy of 3.5 GeV carried by the proton. The high statistic of measured Λ hyperons allows us to perform a double differential analysis in Lorentz-invariant observables of transverse momentum and rapidity. We present the analysis method and a comparison with simulations.

Highlights

The interaction of hyperons such as Λ, Σ, Ξ in a nuclear environment may have a strong overlap with astrophysics observables
We analyze experimental data of Λ hyperons measured with the HADES detector in p+93Nb reactions with a kinetic beam energy of 3.5 GeV carried by the proton
There are models [1] predicting that because of energetically reasons it is favorable that a conversion of nucleons to hyperons via the weak interaction takes place in high density regions, like in the core of neutron stars

Summary

Introduction

The interaction of hyperons such as Λ, Σ, Ξ in a nuclear environment may have a strong overlap with astrophysics observables. The appearance of additional degrees of freedom at high densities leads, eventually, to a softening of the nuclear equation of state. Such a softening implicates lower neutron star masses. Microscopic models with hyperon content can predict neutron star masses and be compared to a recent finding of a two solar mass neutron star [2]. These models use as an input and starting point the hyperon-nucleon interaction strength at saturation density and extrapolate to higher densities. Because of the large detector acceptance we were able to extract a high statistic Λ sample

The method to analyze Λ hyperons

Preliminary results

Summary and Outlook