Seminar by Prof. Frank Deppisch
Title: Probing New Physics in Neutrinoless Double Beta Decay: From Standard Mechanisms to Exotic Signatures
Speaker: Prof. Frank Deppisch, University College London, UK
Abstract: Neutrinoless double beta decay remains our most sensitive laboratory probe of total lepton number violation and the Majorana nature of neutrinos. While the standard paradigm focuses on the exchange of light Majorana neutrinos, a broad class of Beyond the Standard Model (BSM) scenarios predicts alternative short- and long-range mechanisms, as well as exotic multi-body emission modes that significantly alter experimental kinematics. In this seminar, I will first review the theoretical foundations of neutrinoless double beta decay, connecting low-energy effective field theory descriptions and nuclear matrix element uncertainties to high-scale neutrino mass generation mechanisms. I will then focus on recent theoretical developments that expand the discovery potential of current and next-generation ton-scale experiments. In particular, I will discuss how the on-shell production of light, weakly coupled states, such as long-lived Majoron-like scalars, can lead to visible displaced decays within a double beta decay detector, reshaping the summed-electron energy spectrum and providing distinct topological signatures.
Venue: Seminar Room (202), Physics Department IIT Bombay, Powai, Mumbai