Fast neutrino flavor conversions in one-dimensional core-collapse supernova models with and without muon creation

In very dense environments, neutrinos can undergo fast flavor conversions on scales as short as a few centimeters provided that the angular distribution of the neutrino lepton number crosses zero. This work presents the first attempt to establish whether the non-negligible abundance of muons and their interactions with neutrinos in the core of supernovae can affect the occurrence of such crossings. For this purpose we employ state-of-the-art one-dimensional core-collapse supernova simulations, considering models that include muon-neutrino interactions as well as models without these reactions. Although a consistent treatment of muons in the equation of state and neutrino transport does not seem to modify significantly the conditions for the occurrence of fast modes, it allows for the existence of an interesting phenomenon, namely fast instabilities in the $\mu-\tau$ sector. We also show that crossings below the supernova shock are a relatively generic feature of the one-dimensional simulations under investigation, which contrasts with the previous reports in the literature. Our results highlight the importance of multi-dimensional simulations with muon creation, where our results must be tested in the future.