Authors
Suzuki, K. N. ; Gogami, T.; Pandy, B.; Itabashi, K.; Nagao, S.; Okuyama, K.; Nakamura, S. N. ; Tang, L.; Abrams, D. ; Akiyama, T. ; Reimer, P.; Riordan, S.
Abstract
The small binding energy of hypertrition leads to predictions of non-existence of bound hypernuclei for the isotriplet three-body system such as nn. However, invariant mass spectroscopyat GSI reported events that may be interpreted as the bound nn state. The nn state wassearched for by missing-mass spectroscopy via the (e, e0K+) reaction at the Jefferson Labsexperimental Hall A. The present experiment has higher sensitivity to the nn-state investigation in terms of the better precision by a factor of about three than the previous invariant massspectroscopy. The analysis shown in this article focuses on the derivation of the reaction-crosssection for the 3H(, K+)X reaction. Events that were detected in an acceptance, where aMonte Carlo simulation could reproduce the data well (|p/p| < 4%), were analyzed to minimize the systematic uncertainty. No significant structures were observed with the acceptancecuts, and the upper limits of the production-cross section of nn state were obtained to be 21and 31 nb/sr at the 90%-confidence level when theoretical predictions of (B, ) = (0.25, 0.8)and (0.55, 4.7) MeV, respectively, were assumed. The cross-section result provides valuableinformation to examine the existence of nn.