2025/09/21 by Akaishi, T., Asano, H., Chen, X. +32
#FOS: Physical sciences #Nuclear Experiment (nucl-ex)
paper · doi:10.48550/arxiv.2509.16967
Light s-shell hypernuclei (3,4ΛH) and their ground-state properties are crucial benchmarks in hypernuclear physics. In particular, comparing the production cross sections of 3ΛH and 4ΛH provides insights into the ΛN interaction in different isospin configurations, which can help address recent discrepancies in the reported Λ binding energy of hypertriton. We present the first measurement of the production cross sections for 3ΛH and 4ΛH using the in-flight (K-, π0) reaction at a beam momentum of 1.0 GeV/c with an identical experimental setup. The production cross sections in the laboratory frame, for the angular range from 0∘ to 20∘, are measured to be 15.0~±~2.6~(stat.)~+2.4-2.8~(syst.)~μb and 49.9~±~2.1~(stat.)~+7.8-8.0~(syst.)~μb for the ground-state of 3ΛH and 4ΛH, respectively. Using the ratio of these cross sections and comparing it with theoretical calculations, we evaluate the Λ binding energy of hypertriton, yielding a value consistent with the picture of a loosely bound system.