Spectroscopic study of a possible Λnn resonance and a pair of ΣNN states using the (e…

A mass spectroscopy experiment with a pair of nearly identical high-resolution spectrometers and a tritium target was performed in Hall A at Jefferson Lab. Utilizing the (e,e′K+) reaction, enhancements, which may correspond to a possible Λnn resonance and a pair of ΣNN states, were observed with an energy resolution of about 1.21 MeV (σ), although greater statistics are needed to make definitive identifications. An experimentally measured Λnn state may provide a unique constraint in determining the Λn interaction, for which no scattering data exist. In addition, although bound A=3 and 4 Σ hypernuclei have been predicted, only an A=4 Σ hypernucleus (HeΣ4) was found, utilizing the (K−,π−) reaction on a He4 target. The possible bound ΣNN state is likely a Σ0nn state, although this has to be confirmed by future experiments.Received 10 July 2020Revised 9 March 2022Accepted 9 May 2022DOI:https://doi.org/10.1103/PhysRevC.105.L051001©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBinding energy & massesFew-body systemsMeson & hyperon induced nuclear reactionsNucleon-nucleon interactionsParticle interactionsPhysical SystemsHyperonsPropertiesA ≤ 5Nuclear PhysicsParticles & Fields