Improved $\Lambda p$ Elastic Scattering Cross Sections Between 0.9 and 2.0 GeV/c and Connections to the Neutron Star Equation of State

TL;DR

This paper presents new, precise measurements of Lambda-proton elastic scattering cross sections between 0.9 and 2.0 GeV/c, providing critical data for understanding hyperon interactions in neutron star cores.

Contribution

It provides the first updated data on Lambda-proton elastic scattering in decades, improving accuracy and precision, and introduces techniques applicable to future hyperon-nucleon scattering experiments.

Findings

New cross section data with better accuracy and precision

First data on Lambda-proton elastic scattering in decades

Techniques developed can be used in future experiments

Abstract

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state (EOS). Yet, compared to other elastic scattering processes, there is very little data on $\Lambda$-$N$ scattering. This experiment utilized the CLAS detector to study the $\Lambda p \rightarrow \Lambda p$ elastic scattering cross section in the incident $\Lambda$ momentum range 0.9-2.0 GeV/c. This is the first data on this reaction in several decades. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.