000002770 001__ 2770 000002770 005__ 20211124144025.0 000002770 037__ $$aBELLE2-POSTER-CONF-2021-001 000002770 041__ $$aeng 000002770 100__ $$aHuw Haigh 000002770 245__ $$aPunzi-loss 000002770 260__ $$aACAT 2021$$c2021-11-24 000002770 300__ $$amult. p 000002770 520__ $$aThe search for new particles requires robust classification methods, with the ability to be optimised for unknown cross sections and particle masses. We present a new loss function, 'Punzi-loss', based on the so-called Punzi figure of merit (FOM). We refer to a neural network trained with the Punzi-loss function as a 'Punzi-net', and investigate its application to the search for invisible decays of the hypothetical Z' boson produced in the process e+e- -> mu+mu-Z' at the Belle II experiment. 000002770 8560_ $$fhuw.haigh@oeaw.ac.at 000002770 8564_ $$uhttps://docs.belle2.org/record/2770/files/BELLE2-POSTER-CONF-2021-001.pdf