Fig. 3: Training image and model performance on NAGARA event.

a displays the topology of a double-Λ hypernuclear event generated with Geant4 Monte Carlo simulations. One of the example images for the training of the machine learning model (Mask R-CNN), including an image of a goal object (b) and the images with its mask image (c). d shows the images of the NAGARA event taken from ref. ¹⁹, which is the only uniquely identified double-Λ hypernuclear event thus far. e is the input image of the Nagara event for the developed model. f shows the detection result of the developed model for the NAGARA event.