Complementarity between atmospheric and super-beam neutrinos at ESSnuSB

Abstract

The ESSnuSB experiment aims to measure the leptonic CP phase $\hat{I}{´}_{CP}$ with an unprecedented resolution by probing neutrino oscillations at the second oscillation maximum. In the present work, the complementarity between the long-baseline neutrino program and atmospheric neutrinos is investigated for ESSnuSB. By simulating atmospheric neutrino events equivalent of 5.4 Mt$\cdot$year exposure, the resolution for $\hat{I}{´}_{\mathrm{CP}}^{}$ is found to improve from $7.5^{\circ }$ ($6.7^{\circ }$) to $7.1^{\circ }$ ($6.5^{\circ }$) at $1\ddot{I}ƒ$~CL for $\hat{I}{´}_{\mathrm{CP}}^{}=-90^{\circ }$ ($+90^{\circ }$) with respect to super-beam neutrinos, resolving also the degeneracies arising from neutrino mass ordering. These findings highlight the synergies that exist between super-beam neutrinos and atmospheric neutrinos in ESSnuSB.

14 pages, 7 figures, 2 tables