Revisiting the former nuclear emulsion data for hypertriton

We revisit previous measurements for the hypertriton binding energy with nuclear emulsion which were published in 1968 and 1973. Using Monte Carlo simulations, the systematic error of the hypertriton binding energy in emulsion measurements has been estimated to be approximately 28 keV. We corroborate the recent works that re-evaluate the hypertriton binding energy by using the former emulsion measurements in the present work, and the ambiguities and difficulties of the reevaluation are observed. Considering the need of new precise measurements with a well-controlled systematic error, we introduce a new approach by analyzing the existing nuclear emulsion data from the J-PARC E07 experiment, from which the binding energy of hypertriton could be determined, with both statistical and systematic errors, to be approximately 30 keV with 400 events.