Unraveling the Hyperon Puzzle in Neutron Stars via Novel, High-Precision Hyperon Factories

TL;DR

This paper proposes using hyperons produced in proton-proton collisions as high-quality sources to study hyperon-nucleon interactions, aiming to resolve the hyperon puzzle in neutron stars.

Contribution

It introduces a novel experimental approach utilizing copiously produced hyperons in fixed target experiments for precise hyperon interaction measurements.

Findings

Hyperons can be produced abundantly in $pp$ collisions with known kinematics.

The method enables high-precision studies of hyperon interactions with various targets.

This approach can be integrated into existing and planned experiments at FAIR and HIAF.

Abstract

The strong forces between nucleons ($N$=$p$, $n$) are fundamental to the visible universe. The interactions between hyperons (baryons with strange quarks) and nucleons are essential for the intrinsic properties of neutron stars. Whereas the interactions between nucleons ($pp$, $pn$, $nn$) have been extensively studied, the interactions between nucleons and hyperons ($N\Lambda$, $N\Sigma$, $N\Xi$, $N\Omega$, ...) are not well understood, due to the small amount of relevant data, limited by the scarcity of suitable hyperon sources. Here we point out and investigate a new high-quality source: hyperons produced in $pp$ collisions, such as $pp\to pK^+\Lambda$, $pK\Sigma$, $pK\pi\Sigma$, $pKK\Xi$, $pKKK\Omega$. At a fixed target experiment using proton beam with known momentum and liquid hydrogen target, $pp\to pK^+\Lambda$ can be produced copiously. By tagging $p$ and $K^+$, the flux and momentum of the $\Lambda$ can be determined precisely. By placing an additional target around the primary one, these $\Lambda$-s serve as an ideal source, enabling an unprecedentedly precise study of $\Lambda$ interactions with a wide range of targets. Similar methods can be used to obtain high-quality sources of other hyperons, such as $\Sigma$, $\Xi$ and $\Omega$. These novel, high-statistics sources of hyperons with precisely known kinematics present new opportunities for applications in particle and nuclear physics, particularly in understanding the hyperon puzzle of neutron stars. We propose a new high-luminosity experiment with two nested concentric targets, optimized for such measurements. This concept can also be incorporated into existing experiments, such as HADES and CBM at FAIR, as well as proposed experiments, such as H-NS and HHaS at HIAF, by adding a second target without significant modification of the current detectors.