Letter of intent for KM3NeT 2.0

TLDR

The project is motivated by IceCube’s detection of high‑energy astrophysical neutrinos and by measurements of electron neutrino contributions to the third mass eigenstate from Daya Bay, Reno, and related experiments. The collaboration aims to discover and observe high‑energy neutrino sources and to determine the neutrino mass hierarchy. They will construct a phased, distributed network of deep‑sea telescopes across three Mediterranean sites, comprising building blocks of 115 strings each with 18 optical modules of 31 PMTs, to detect Cherenkov light from neutrino interactions and study both IceCube‑like signals and atmospheric neutrino oscillations.

Abstract

The main objectives of the KM3NeT Collaboration are (i) the discovery and subsequent observation of high-energy neutrino sources in the Universe and (ii) the determination of the mass hierarchy of neutrinos. These objectives are strongly motivated by two recent important discoveries, namely: (1) the high-energy astrophysical neutrino signal reported by IceCube and (2) the sizable contribution of electron neutrinos to the third neutrino mass eigenstate as reported by Daya Bay, Reno and others. To meet these objectives, the KM3NeT Collaboration plans to build a new Research Infrastructure consisting of a network of deep-sea neutrino telescopes in the Mediterranean Sea. A phased and distributed implementation is pursued which maximises the access to regional funds, the availability of human resources and the synergistic opportunities for the Earth and sea sciences community. Three suitable deep-sea sites are selected, namely off-shore Toulon (France), Capo Passero (Sicily, Italy) and Pylos (Peloponnese, Greece). The infrastructure will consist of three so-called building blocks. A building block comprises 115 strings, each string comprises 18 optical modules and each optical module comprises 31 photo-multiplier tubes. Each building block thus constitutes a three-dimensional array of photo sensors that can be used to detect the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be sparsely configured to fully explore the IceCube signal with similar instrumented volume, different methodology, improved resolution and complementary field of view, including the galactic plane. One building block will be densely configured to precisely measure atmospheric neutrino oscillations.