Probing CPT breaking induced by quantum decoherence at DUNE

Abstract

We show that the decoherence phenomena applied to the neutrino system could lead to an observable breaking of the fundamental $CPT$ symmetry. We require specific textures of nondiagonal decoherence matrices, with nonzero ${\ensuremath{\delta}}_{CP}$, for making such observations. Using the information from the $CPT$ conjugate channels ${\ensuremath{\nu}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ and ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ and their corresponding backgrounds, we have estimated the sensitivity of the DUNE experiment for testing $CPT$ under the previous conditions. Four scenarios for energy-dependent decoherence parameters, ${\mathrm{\ensuremath{\Gamma}}}_{{E}_{\ensuremath{\nu}}}=\mathrm{\ensuremath{\Gamma}}\ifmmode\times\else\texttimes\fi{}({E}_{\ensuremath{\nu}}/\mathrm{GeV}{)}^{n}$, $n=\ensuremath{-}1$, 0, 1, and 2, are taken into account, and for most of them, DUNE is able to achieve a $5\ensuremath{\sigma}$ discovery potential, having $\mathrm{\ensuremath{\Gamma}}$ in $\mathcal{O}({10}^{\ensuremath{-}23}\text{ }\text{ }\mathrm{GeV})$ for ${\ensuremath{\delta}}_{CP}=3\ensuremath{\pi}/2$. Meanwhile, for ${\ensuremath{\delta}}_{CP}=\ensuremath{\pi}/2$, we reach $3\ensuremath{\sigma}$ for $\mathrm{\ensuremath{\Gamma}}$ in $\mathcal{O}({10}^{\ensuremath{-}24}\text{ }\text{ }\mathrm{GeV})$.