Constraining the isotropic CPT-odd coefficients of the Standard Model Extension by a combined DUNE and ESSnuSB analysis

Abstract

Based on an analysis that considers the isotropic CPT-odd Standard Model Extension (SME) coefficients, we find new constraints for them coming from a combined DUNE and ESSnuSB fit. Furthermore, we investigate the correlations of the standard oscillation parameters, the leptonic CP-violating phase, $\delta_{CP}$, and the atmospheric mixing angle, $\sin^2 \theta_{23}$, with respect to the SME coefficients $(a_L)^T$. The combination of DUNE and ESSnuSB may establish the strongest limit on the diagonal coefficient $(a_L)_{\mu \mu}^T$ compared to the existing limits in the literature. We also consider the possible effect of the SME coefficient $(a_L)^Z$ on neutrino propagation and discuss how this can affect DUNE limits on the coefficient $(a_L)^T$ found elsewhere.