Conference for Neutrino and Nuclear Physics, CNNP2020

In February 2020, everyone all over the world started to become acutely aware of the dangers posed by a new virus sweeping the globe. Yet, still, humanity was naively thinking that this problem would pass, like so many before it, without too much of a disruption to our lives. With reports of the COVID-19 virus detected in numerous countries across the globe in the back of their minds, physicists from all over the world converged on the Arabella Hotel and Spa, located in the beautiful Kogelberg Biosphere close to Cape Town, to start the second Conference on Neutrino and Nuclear Physics (CNNP), hosted by iThemba Laboratories for Accelerator Based Sciences and held from 24 to 28 February 2020. The main objective of the CNNP series is to promote collaboration between scientists from the fields of nuclear, neutrino, astro-, and dark-matter physics. Toward this end, the topics discussed at the conference included nuclear double-beta decays, nuclear structure in connection with neutrino physics, nuclear reactions as probes for weak decays, neutrino–nucleus interaction at low and high energies, supernova models and detection of supernovae neutrinos, solar models and detection of solar neutrinos, direct and indirect dark-matter searches, rare beta decays of nuclei for neutrinomass measurements, neutrino oscillations and matter effects, and new detection technologies. The conference was attended by 91 delegates. The program included presentations by invited speakers, suggested by the International Advisory Committee, as well as contributed talks. Approved presentations from the invited speakers can be accessed via the CNNP2020 YouTube channel (https://www.youtube.com/channel/ UCQGnk_Ar_2Cn13UNm1zgdHQ/ videos). Twenty masters and doctoral students studying at South African universities attended the first two days of the conference. A special poster session sponsored by the iThemba LABS SAINTS (Southern African Institute for Nuclear Technology and Sciences) was organized to allow these students, doing research in basic/applied nuclear physics, to exhibit the range of topics in nuclear physics studied at South African universities. From the scientific program it was clear that significant progress was made on many fronts since the inaugural Conference on Neutrino and Nuclear Physics (CNNP2017), which was held in Catania in October 2017. In a crescendo of presentations, recent theoretical advances in the calculation of nuclear matrix elements were shared using effective field theory as well as large-scale shell-model calculations. Not only do these advances impact the potential for extracting the neutrino mass from neutrinoless double-beta decay lifetimes, but it was demonstrated that the expansion of the scope of ab initio theory to global calculations of nuclei can lead to a possible solution of the long-standing g A quenching puzzle. Notable improvements were also reported for neutrinoless double-beta decay lifetime limits, as well as reductions of exclusion regions for dark-matter searches, while huge strides were made since CNNP2017 regarding quantative predictions of double charge exchange reaction spectra. Little did the physics community realize that this would be the last inperson conference hosted by iThemba LABS for quite a while! Five days after the closing session of CNNP2020, it was confirmed that the SARS-CoV-2 virus spread to South Africa and, ten days later, a national state of disaster was declared. South Africa, together with most of the world, went into lockdown. The next conference in the CNNP series will be hosted by Oak Ridge National Laboratory in the northern hemisphere, spring 2023. Additional information about CNNP2020 is available at https://indico.tlabs.ac.za/ event/85/.