Physics reach of DUNE with a light sterile neutrino

We investigate the implications of one light eV scale sterile neutrino on the physics potential of the proposed long-baseline experiment DUNE. If the future short-baseline experiments confirm the existence of sterile neutrinos, then it can affect the mass hierarchy (MH) and CP-violation (CPV) searches at DUNE. The MH sensitivity still remains above 5σ if the three new mixing angles (θ 14, θ 24, θ 34) are all close to θ 13. In contrast, it can decrease to 4σ if the least constrained mixing angle θ 34 is close to its upper limit ∼ 300. We also assess the sensitivity to the CPV induced both by the standard CP-phase δ 13 ≡ δ, and the new CP-phases δ 14 and δ 34. In the 3+1 scheme, the discovery potential of CPV induced by δ 13 gets deteriorated compared to the 3ν case. In particular, the maximal sensitivity (reached around δ 13 ∼ ± 900) decreases from 5σ to 4σ if all the three new mixing angles are close to θ 13. It can further diminish to almost 3σ if θ 34 is large (∼ 300). The sensitivity to the CPV due to δ 14 can reach 3σ for an appreciable fraction of its true values. Interestingly, θ 34 and its associated phase δ 34 can influence both the ν e appearance and ν μ disappearance channels via matter effects, which in DUNE are pronounced. Hence, DUNE can also probe CPV induced by δ 34 provided θ 34 is large. We also reconstruct the two phases δ 13 and δ 14. The typical 1σ uncertainty on δ 13 (δ 14) is ∼ 200 (300) if θ 34 = 0. The reconstruction of δ 14 (but not that of δ 13) degrades if θ 34 is large.