Spectroscopy of Lambda-9Li by electroproduction

TL;DR

This study presents the first electroproduction spectroscopy of Lambda-9Li hypernucleus with high energy resolution, providing new experimental data on hyperon-nucleon interactions and hypernuclear structure.

Contribution

It introduces a novel experimental approach with enhanced detection capabilities to study Lambda-9Li, offering detailed spectral data and comparison with theoretical models.

Findings

Spectra concentrated within 3 MeV of ground state

Measured Lambda separation energy of 8.36 MeV

Observed agreement and discrepancies with theoretical predictions

Abstract

In the absence of accurate data on the free two-body hyperon-nucleon interaction, the spectra of hypernuclei can provide information on the details of the effective hyperon-nucleon interaction. Electroproduction of the hypernucleus Lambda-9Li has been studied for the first time with sub-MeV energy resolution in Hall A at Jefferson Lab on a 9Be target. In order to increase the counting rate and to provide unambiguous kaon identification, two superconducting septum magnets and a Ring Imaging CHerenkov detector (RICH) were added to the Hall A standard equipment. The cross section to low-lying states of Lambda-9Li is concentrated within 3 MeV of the ground state and can be fitted with four peaks. The positions of the doublets agree with theory while a disagreement could exist with respect to the relative strengths of the peaks in the doublets. A Lambda separation energy of 8.36 +- 0.08 (stat.) +- 0.08 (syst.) MeV was measured, in agreement with an earlier experiment.