Model-independent constraints on non-unitary neutrino mixing from high-precision long-baseline experiments

A bstract Our knowledge on the active 3 ν mixing angles ( θ 12 , 13 and 23 ) CP phase δ is becoming accurate day-by-day enabling us to test unitarity of leptonic matrix with utmost precision. Future high-precision long-baseline experiments are going play an important role in this direction. In work, we study impact possible non-unitary neutrino (NUNM) context next-generation DUNE T2HKK/JD+KD having one detector Japan (T2HK/JD) a second Korea (KD). We estimate sensitivities these setups place direct, model-independent, competitive constraints various NUNM parameters. demonstrate correlations between parameters, . numerical results obtained using only far data supported by simple approximate analytical expressions oscillation probabilities matter, reveal that JD+KD has better for |α 21 | α 22 as compared DUNE, due its larger statistics appearance channel less systematic uncertainties disappearance channel, respectively. For 31 32 33 gives JD+KD, matter effect wider energy spectrum. 11 both give similar bounds. also show how much bounds parameters can be improved combining prospective from setups. find zero-distance effects, near detectors alone constrain Finally, observe τ sample improve