アイテム詳細

要旨

Light sterile neutrinos are frequently proposed to explain the short-baseline anomalies or as dark matter candidates, requiring non-zero mixing with the active neutrinos. This mixing not only impacts neutrino oscillations, but also induces contributions to the mass matrix of the active neutrinos, a factor often overlooked in the literature. We consider a 3 + 1 Majorana neutrino scheme, for which we present the current bounds on sterile neutrino mass and mixings and use them to derive constraints on the induced mass contributions for each entry of the active neutrino mass matrix. Our analysis examines whether this model-independent approach can affect neutrino masses and mixings within a UV-complete neutrino mass model, demonstrating that the experimentally disfavoured Zee-Wolfenstein model can be revived within a minimally extended framework including a single sterile neutrino, making it consistent with oscillation data. Furthermore, we discuss how oscillation data and 0νββ decay provide complementary constraints on the sterile neutrino parameter space, utilizing the latest KamLAND-Zen data to highlight significant challenges for the sterile neutrino parameter space suggested by short-baseline anomalies, with future experiments potentially ruling out large regions of this parameter space.