The cross-section measurement for the 3H(e, e′K+)nnΛ reaction

Abstract

The small binding energy of hypertrition leads to predictions of non-existence of bound hypernuclei for the isotriplet three-body system such as nnΛ. However, invariant mass spectroscopy at GSI reported events that may be interpreted as the bound nnΛ state. The nnΛ state was searched for by missing-mass spectroscopy via the (e, e′K+) reaction at the Jefferson Lab’s experimental Hall A. The present experiment has higher sensitivity to the nnΛ-state investigation in terms of the better precision by a factor of about three than the previous invariant mass spectroscopy. The analysis shown in this article focuses on the derivation of the reaction-cross section for the 3H(γ*, K+)X reaction. Events that were detected in an acceptance, where a Monte Carlo simulation could reproduce the data well ($|\delta p/p| < 4\%$), were analyzed to minimize the systematic uncertainty. No significant structures were observed with the acceptance cuts, and the upper limits of the production-cross section of nnΛ state were obtained to be 21 and $31~\rm {nb/sr}$ at the 90%-confidence level when theoretical predictions of ( − BΛ, Γ) = (0.25, 0.8) and (0.55, 4.7) MeV, respectively, were assumed. The cross-section result provides valuable information to examine the existence of nnΛ.

Study of the Λ/Σ0 electroproduction in the low-Q2 region at JLab

“…In the present paper, the data using the gaseous hydrogen target in the E12-17-003 experiment [1,2] (Q 2 ≃ 0.5 (GeV/c) 2 , W = 2.14 GeV, and θ c.m. γK ≃ 8 deg) was analyzed, and the differential cross sections for the p(e, e ′ K + )Λ/Σ 0 reaction were obtained.…”

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In 2018, the E12-17-003 experiment was conducted at the Thomas Jefferson National Accelerator Facility (JLab) to explore the possible existence of an nnΛ state in the reconstructed missing mass distribution from a tritium gas target [1,2]. As part of this investigation, data was also collected

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