A multi-cubic-kilometre neutrino telescope in the western Pacific Ocean

TL;DR

This paper proposes a next-generation neutrino telescope in the western Pacific Ocean, detailing site selection, water properties, design, and its potential to significantly advance astrophysical neutrino detection and cosmic ray research.

Contribution

It introduces the TRIDENT telescope concept, including site-specific measurements and expected performance, enhancing global neutrino observation capabilities.

Findings

Identified a suitable deep-sea site at 3.5 km depth

Measured water absorption and scattering lengths for Cherenkov light

Projected detection of NGC 1068 with 5σ significance within 1 year

Abstract

Next-generation neutrino telescopes with significantly improved sensitivity are required to pinpoint the sources of the diffuse astrophysical neutrino flux detected by IceCube and uncover the century-old puzzle of cosmic ray origins. A detector near the equator will provide a unique viewpoint of the neutrino sky, complementing IceCube and other neutrino telescopes in the Northern Hemisphere. Here we present results from an expedition to the north-eastern region of the South China Sea, in the western Pacific Ocean. A favorable neutrino telescope site was found on an abyssal plain at a depth of $\sim$ 3.5km. At depths below 3km, the sea current speed, water absorption and scattering lengths for Cherenkov light, were measured to be $v_{\mathrm{c}}<$10cm/s, $\lambda_{\mathrm{abs} }\simeq$ 27m and $\lambda_{\mathrm{sca} }\simeq$ 63m, respectively. Accounting for these measurements, we present the design and expected performance of a next-generation neutrino telescope, TRopIcal DEep-sea Neutrino Telescope (TRIDENT). With its advanced photon-detection technology and large dimensions, TRIDENT expects to observe the IceCube steady source candidate NGC 1068 with 5$\sigma$ significance within 1 year of operation. This level of sensitivity will open a new arena for diagnosing the origin of cosmic rays and probing fundamental physics over astronomical baselines.