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

• Published in: Progress of theoretical and experimental physics Vol. 2022; no. 1
• Main Authors: Suzuki, K N, Gogami, T, Pandey, B, Itabashi, K, Nagao, S, Okuyama, K, Nakamura, S N, Tang, L, Abrams, D, Akiyama, T, Androic, D, Aniol, K, Gayoso, C Ayerbe, Bane, J, Barcus, S, Barrow, J, Bellini, V, Bhatt, H, Bhetuwal, D, Biswas, D, Camsonne, A, Castellanos, J, Chen, J-P, Chen, J, Covrig, S, Chrisman, D, Cruz-Torres, R, Das, R, Fuchey, E, Gnanvo, K, Garibaldi, F, Gautam, T, Gomez, J, Gueye, P, Hague, T J, Hansen, O, Henry, W, Hauenstein, F, Higinbotham, D W, Hyde, C E, Kaneta, M, Keppel, C, Kutz, T, Lashley-Colthirst, N, Li, S, Liu, H, Mammei, J, Markowitz, P, McClellan, R E, Meddi, F, Meekins, D, Michaels, R, Mihovilovič, M, Moyer, A, Nguyen, D, Nycz, M, Owen, V, Palatchi, C, Park, S, Petkovic, T, Premathilake, S, Reimer, P E, Reinhold, J, Riordan, S, Rodriguez, V, Samanta, C, Santiesteban, S N, Sawatzky, B, Širca, S, Slifer, K, Su, T, Tian, Y, Toyama, Y, Uehara, K, Urciuoli, G M, Votaw, D, Williamson, J, Wojtsekhowski, B, Wood, S A, Yale, B, Ye, Z, Zhang, J, Zheng, X
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 21.01.2022
• Subjects: Monte Carlo simulation; Spectrum analysis
• ISSN: 2050-3911; 2050-3911
• DOI: 10.1093/ptep/ptab158

Abstract The small binding energy of the hypertriton leads to predictions of the non-existence of bound hypernuclei for isotriplet three-body systems such as nnΛ. However, invariant mass spectroscopy at GSI has reported events that may be interpreted as the bound nnΛ state. The nnΛ state was sought by missing-mass spectroscopy via the (e, e′K+) reaction at Jefferson Lab’s experimental Hall A. The present experiment has higher sensitivity to the nnΛ-state investigation in terms of better precision by a factor of about three. 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 ($|\delta p/p| \lt 4\%$), 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 the nnΛ state were obtained to be 21 and $31 \, \rm {nb} \, \rm {sr}^{-1}$ at the $90\%$ confidence level when theoretical predictions of (−BΛ, Γ) = (0.25, 0.8) MeV and (0.55, 4.7) MeV, respectively, were assumed. The cross-section result provides valuable information for examining the existence of nnΛ.