A New Pathway to the Gallium Anomaly: Population of the Isobaric Analog State in 71Ge

Experimental studies of nuclear matrix elements (NMEs) related to neutrinoless double-beta-decays (DBDs) and astroneutrino inverse beta decays (IBDs) are essential for advancing our understanding of neutrino physics beyond the Standard Model, as well as for astro-neutrino research. Accurate theoretical calculations of NMEs are challenging due to their strong sensitivity to the nuclear models and parameters used. However, key NMEs associated with electromagnetic transition operators in both DBD and IBD processes – such as effective weak couplings – can be experimentally determined by measuring the corresponding electromagnetic (gamma) transitions from the isobaric analog states (IASs) of the relevant nuclei. To address this, the GAMMA group at the I.N.F.N. Laboratori Nazionali di Legnaro (Italy) has launched an innovative experimental campaign aimed at exploring the interface between gamma spectroscopy and neutrino physics. The thesis work involves participation in the preparation of the experimental setup and in the data analysis of the first experiment of the campaign, which focuses on studying the population cross-section of the IAS of 71Ga in 71Ge through a (p,d) reaction on 72Ge.