Search

JLab E12-19-002 Experiment is planned to measure the Λ-binding energies of 3ΛH [Jπ = 1/2+ or 3/2+(T = 0)] and 4ΛH (1+) at JLab Hall C. The expected accuracy for the binding-energy measurement is |ΔBtotal Λ | ≃ 70 keV. The accurate spectroscopy for these light hypernuclei would shed light on the puzzle of the small binding energy and short lifetime of 3ΛH, and the chargesymmetry breaking in the ΛN interaction. We aim to perform the experiment in 2025.

An n n Λ , which consists of two neutrons and a Lambda hyperon, is a multi-baryon system with no charge. Studying the n n Λ state would provide information about the Λ n interaction which has not been directly measured by a scattering experiment. The experiment (E12-17-003) was performed in order to search for the n n Λ state at Jefferson Lab. The n n Λ is expected to be produced by the (e , e ′ K +) reaction, which has sensitivity to both bound and resonance states if the natural width of the n n Λ is narrow enough to be observed as a peak. The experiment used gas targets of hydrogen and tritium for mass calibration and the n n Λ production, respectively. The mass calibration with H (e , e ′ K +) Λ / Σ 0 reactions gave the mass resolution of the Λ and Σ 0 each 3.5 MeV / c 2 FWHM, for the elementary reaction. A spectrum of 3 H (e , e ′ K +) X was obtained, and a simple model with a Λ n final state interaction was applied to reproduce the spectrum. [ABSTRACT FROM AUTHOR]