Combined sensitivity of JUNO and KM3NeT/ORCA to the neutrino mass ordering

Abstract

This article presents the potential of a combined analysis of the JUNO and KM3NeT/ORCA experiments to determine the neutrino mass ordering. This combination is particularly interesting as it significantly boosts the potential of either detector, beyond simply adding their neutrino mass ordering sensitivities, by removing a degeneracy in the determination of ∆$$ {m}_{31}^2 $$ m 31 2 between the two experiments when assuming the wrong ordering. The study is based on the latest projected performances for JUNO, and on simulation tools using a full Monte Carlo approach to the KM3NeT/ORCA response with a careful assessment of its energy systematics. From this analysis, a 5σ determination of the neutrino mass ordering is expected after 6 years of joint data taking for any value of the oscillation parameters. This sensitivity would be achieved after only 2 years of joint data taking assuming the current global best-fit values for those parameters for normal ordering.

New reactor data improves robustness of neutrino mass ordering determination

“…Therefore, the agreement of the results from SNO (in matter) [58] and of the results from KamLAND (in vacuum) [59] or pp solar oscillations (in vacuum) [60][61][62] breaks this degeneracy. This allows JUNO [63] or a combination of JUNO and upcoming atmospheric disappearance data [64,65] to measure the atmospheric mass ordering [66] without an independent measurement of the atmospheric mass 2 This is what spawned the name LMA-Dark. 3 Here we take the definition of the mass eigenstates based on 2 21 > 0 by definition and the octant of θ 12 is to be determined experimentally.…”

“…Here, N and Z are the number of neutrons and protons in the target nucleus which we take as (N, Z) = (40. 65,32) for Ge, corresponding to the weighted average of natural isotopic abundance. The SM couplings of the Z boson to protons and neutrons at low energies are given by [82] g…”

Scalable solutions for the Control Unit of the KM3NeT DAQ system

“…The KM3NeT Collaboration is incrementally building and operating two neutrino telescopes in the Mediterranean Sea: ARCA † , located off the shore of Sicily is devoted to neutrino astronomy ( [1]); ORCA ‡ , off the French shore is optimised for the study of neutrino oscillations ( [2], [3], [4]). Both are water Cherenkov detectors with 3D lattices of DOMs (Digital Optical Modules) [5], each hosting 31 PMTs (photomultipliers) plus a compass, tiltmeter and humidity and pressure sensors, all controlled by a CLB (Central Logic Board); DOMs are grouped in DUs (Detection Units), which are vertical strings, few hundred meters tall, anchored to the seabed, of 18 regularly spaced DOMs.…”