[tw-hepnet] NCTS Seminar - Particle Physics Journal Club 2026/04/20 (Mon.) 12:30

[Yu-Rou Tsang]

***NCTS Seminar***

Particle Physics Journal Club

===================================================

Speaker: Dr. Karolin Hymon (Academia Sinica)

Talk title: POLARIS: A Sparse Radial Neutrino Telescope Design for the Pacific Ocean

Time: 2026/04/20 (Mon.) 12:30

Place: NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU

 

Abstract:
IceCube has established the existence of a diffuse astrophysical neutrino flux and achieved first detections of individual sources, including evidence of emission from NGC 1068 and the Galactic plane. Yet the origin of the majority of this flux remains unknown, and unambiguous point source identification at the 5σ level remains elusive. The recent observation of KM3-230213A, a ~220 PeV near-horizontal muon track, provides concrete evidence that the ultra-high-energy frontier is accessed through horizontal directions, where Earth's opacity above ~100 TeV confines the observable sky to a narrow band near the horizon. I will present POLARIS (Pacific Ocean Large Area Radial Instrumented Sparse array), a sparse radial planar deep-water Cherenkov array of 1100 optical modules in a five-arm geometry, optimized for horizontal νμ tracks and naturally suppressing the downgoing atmospheric background. POLARIS reaches point-source and diffuse flux sensitivities at PeV energies competitive with detectors deploying several times more instrumentation, and complements tau-optimized experiments such as TAMBO and Trinity by providing the muon channel. The design bridges the gap between currently operating telescopes and next-generation projects like TRIDENT and IceCube-Gen2 at a fraction of the cost.