First measurement of $\Lambda N$ inelastic scattering with $\Lambda$ from $e^{+} e^{-} \rightarrow J/\psi \to \Lambda \bar{\Lambda}$

TL;DR

This paper reports the first measurement of inelastic $ ext{Lambda}$-nucleon scattering using $J/ ext{psi}$ decays at an $e^+ e^-$ collider, providing new data on hyperon-nucleon interactions relevant for nuclear physics and astrophysics.

Contribution

It introduces a novel method to measure $ ext{Lambda}$-nucleon interactions at an $e^+ e^-$ collider, yielding the first experimental cross section for this process.

Findings

Measured $ ext{Lambda} + ^{9} ext{Be} ightarrow ext{Sigma}^+ + X$ cross section as $(37.3 extpm 4.7 extpm 3.5)$ mb.

First experimental study of $ ext{Lambda}$-nucleon interactions at an $e^+ e^-$ collider.

Provides constraints for strong-interaction potential and neutron star models.

Abstract

Using an $e^+ e^-$ collision data sample of $(10087 \pm 44)\times10^6 ~J/\psi$ events taken at the center-of-mass energy of $3.097~\rm{GeV}$ by the BESIII detector at the BEPCII collider, the process $\Lambda+N \rightarrow \Sigma^+ + X$ is studied for the first time employing a novel method. The $\Sigma^{+}$ hyperons are produced by the collisions of $\Lambda$ hyperons from $J/\psi$ decays with nuclei in the material of the BESIII detector. The total cross section of $\Lambda + ^{9}{\rm Be} \rightarrow \Sigma^+ + X$ is measured to be $\sigma = (37.3 \pm 4.7 \pm 3.5)~{\rm mb}$ at $\Lambda$ beam momenta within $[1.057, 1.091]~{\rm GeV}/c$, where the uncertainties are statistical and systematic, respectively. This analysis is the first study of $\Lambda$-nucleon interactions at an $e^+ e^-$ collider, providing information and constraints relevant for the strong-interaction potential, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars.