Conveners
NU: NU1 : Application of Neutrino Measurements
- Ibe Masahiro
NU: NU2 : Detectors and Calibrations
- Nobuhiro Shimizu (Chiba University)
NU: NU3 : High-Energy Astrophysical Neutrino Measurements
- Erin O'Sullivan
NU: NU4 : Low-Energy Neutrino Physics
- Shigeki Matsumoto
NU: NU5 : Neutrino Observatories
- Colton Hill (TU Munich)
The measurement of the high-energy atmospheric muon and neutrino fluxes serves as both a fundamental probe of hadronic interaction models and the primary background for astrophysical neutrino searches. Over the last decades, experiments including IceCube, ANTARES, Kamiokande, Frรฉjus, and KM3NeT have provided a wealth of data across different detector media, energy ranges, and zenith angles....
Large-volume neutrino telescopes designed for TeV neutrino astronomy can probe the Earthโs interior through the absorption of atmospheric neutrinos traversing the planet. This provides an independent constraint on the Earthโs radial density profile, complementing conventional methods based on seismic velocity measurements. Such measurements can serve as a cross check of traditional geophysical...
High energy neutrinos and muons produced in the atmospher are dominant backgrounds in astrophysical neutrino detection. Atmospheric neutrinos consist of a conventional component from long-lived meson decays and a prompt component from short-lived charmed hadron decays, where the latter dominates at high energies compared to the conventional component. This prompt flux, which has not yet been...
We report the measurement of the neutrino deep-inelastic scattering cross section using 10 years of IceCube data. At neutrino energies above several hundred GeV experimental constraints remain limited, with measurements from FASER extending to a few TeV and previous IceCube results probing energies above 6.3 TeV, leaving these regimes experimentally disconnected. This analysis extends...
We present a previously-unexplored approach to probing the tau component of the diffuse astrophysical neutrino flux at neutrino telescopes using the visible inelasticity of starting-track events. Tracks from muonic tau decays are biased toward higher inelasticity than those from muon neutrino interactions, providing a statistical handle to separate the two flavors. Using realistic IceCube...
The flavor composition of high-energy neutrinos carries important information about their birth, propagation, and detection. The Glashow resonant interaction $\bar{\nu}_e + e^-\to W^-$ provides a powerful method to differentiate neutrinos and antineutrinos, which expands the potential of flavor composition studies. Proposed tau air shower neutrino telescopes aim to detect earth-skimming and...
The Pacific Ocean Neutrino Experiment (P-ONE) is a planned cubic kilometer neutrino observatory located in the northern Pacific Ocean off the coast of British Columbia, CA. The goal of P-ONE is to detect high-energy astrophysical neutrinos and pinpoint their sources by reconstructing their paths through the detector. P-ONE will consist of ~70 1 km long strings spaced 80 m apart. Each string...
Neutrino point-source searches with IceCube rely on accurate directional reconstruction, requiring realistic simulation of all pulse types in the detector. Afterpulses, delayed secondary pulses in photomultiplier tubes caused by ionization of residual gas, are currently simulated based on laboratory measurements rather than in-ice data, and may not fully capture detector-specific behavior....
TRIDENT is a proposed multi-cubic-kilometer deep-sea neutrino telescope in the South China Sea. In this talk, we first present the status of the TRIDENT Phase-I hybrid Digital Optical Module (hDOM), whose baseline design consists of 31 3-inch PMTs and 21 SiPM arrays. We then report an optimization study for future hDOM designs, based on a candidate configuration with 19 4-inch PMTs and 5 SiPM...
Neutrinos can escape extremely dense astrophysical environments, making them unique probes of cosmic-ray origins and fundamental physics. In water-based neutrino detectors, the longer optical scattering length can offer better pointing resolution than in ice. However, this advantage comes with rapidly varying environmental and detector conditions. Variations in water optical properties,...
The IceCube-Gen2 experiment is a planned expansion of the current IceCube Observatory located beneath the Amundsen-Scott South Pole Station. By increasing the instrumentation volume to approximately 8\text{km}^3 eight times that of the existing detectorโand integrating an in-ice optical sensor array with a surface radio array, the project aims to enhance sensitivity in the high-energy regime...
Baikal-GVD is a cubic-kilometer scale neutrino telescope, optimized for
TeV-PeV neutrino energy range, being constructed in the southern part
of Lake Baikal. The detector is a three-dimensional array of hermetic
containers with enclosed PMTs located at depths between 750 and 1275 m
and organized into independent sub-arrays - clusters. Presently the
telescope includes 16 clusters and its...
The TRopIcal DEep-sea Neutrino Telescope (TRIDENT) is a next-generation neutrino telescope planned in the "Hai-Ling Basin" of the South China Sea at a depth of about 3.5 km. Designed for world-leading sensitivity to high-energy astrophysical neutrinos of all flavours, TRIDENT will instrument a multi-cubic-kilometre volume of seawater with advanced photon-detection technology. As a key step...
IceCube has discovered a flux of galactic and extragalactic neutrinos as well as provided evidence for neutrino emission from two active galaxies, NGC-1068 and TXS 0506+056. Nevertheless, the class of objects responsible for extragalactic neutrinos is unknown; the Milky Way flux is due to an unknown combination of individual sources and diffuse flux due to cosmic ray propagation. Answering...
We present POLARIS, a new sparse radial detector design for an underwater neutrino telescope. The design targets multi-PeV horizontal tracks with a minimal instrumentation density of around 1000 Digital Optical Modules (DOMs). We evaluate the astronomy potential of this design through 5-sigma point source and diffuse flux detection limit, benchmarking against IceCube, KM3NeT ARCA, TRIDENT,...
IceCube-Gen2 is the planned high-energy extension of the current IceCube detector, featuring an optical array nearly eight times larger than that of IceCube and composed of novel optical modules containing multiple photomultiplier tubes (PMTs), providing enhanced and nearly omnidirectional sensitivity. This configuration is expected to significantly increase event statistics and improve the...
We present new results from a measurement of the high-energy astrophysical neutrino flux, featuring an explicit separation into the galactic and extragalactic components. We use the energy and directional information from data collected by the IceCube Neutrino Observatory to resolve the spatial structure of the Galactic plane on the sky while simultaneously measuring the isotropic...
Exhibiting the largest cross-section of all interaction channels for MeV neutrinos, coherent elastic neutrino-nucleus scattering (CEvNS) offers a compelling pathway for the remote monitoring of nuclear reactors. Liquid xenon time projection chambers (LXeTPCs) have emerged as an ideal technology for CEvNS detection, primarily due to their low backgrounds and energy thresholds. The RELICS...
LUX-ZEPLIN (LZ) is the world-leading detector for weakly interacting massive particles (WIMPs) with masses above 5 GeV/c$^2$. Nearly a mile underground at the Sanford Underground Research Facility (SURF), LZ employs a dual-phase xenon time projection chamber with a 7-tonne active volume, augmented by a two-component anti-coincidence veto system. With over 600 kg of $^{136}$Xe in its target...
Solar atmospheric neutrinos in TeV range are important as a background for indirect detection of WIMP annihilation in the Sun. This work presents a flux calculation (up to 100 TeV), which incorporates both the solar magnetic field and neutrino propagation effects. Neutrino production in the magnetic field is simulated using Geant4, while the propagation (with both interaction and oscillation)...
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment in southern China, built 650โฏm underground and positioned 52.5โฏkm from the Yangjiang and Taishan nuclear power plants. Its primary goals are to determine the neutrino mass ordering and measure the oscillation parameters sinยฒฮธโโ, ฮmยฒโโ, and ฮmยฒโโ with unprecedented precision.
To achieve these goals,...
Neutron capture provides a low-energy but distinctive delayed signal that can be exploited in large-volume neutrino telescopes. At TeVโPeV energies, hadronic interactions in neutrino-induced showers produce secondary neutrons. The subsequent neutron capture signals ("neutron echo") offer a powerful tool to distinguish hadronic and electromagnetic components, enabling the separation of...
There has been a long-standing tension in measurements of the neutron lifetime between beam and bottle experiments. It has been established that such a disagreement could be explained by any additional decay channel that does not involve protons in the final state. We present a search using ancient minerals to look for invisible neutron decay, a.k.a. paleodetection. If neutrons in minerals...
The Payload for Ultrahigh Energy Observations (PUEO) is a long-duration balloon experiment designed to search for the astrophysical and cosmogenic neutrino flux at ultrahigh energies (>1 EeV) with world-leading sensitivity. During its successful 23-day Antarctic flight in the 2025-2026 austral summer, PUEO monitored the Antarctic ice sheet for impulsive radio signals characteristic of Askaryan...
Ultra-high-energy neutrinos offer a unique window on the most violent phenomena in the Universe. Produced at astrophysical sources or during cosmic-ray propagation, these unattenuated and unscattered cosmic messengers probe environments inaccessible to other particles. They enable the study of their production sites, may reveal the sources of ultra-high-energy cosmic rays, and help constrain...
The Radio Neutrino Observatory in Greenland (RNO-G) is an in-ice antenna array with 35 planned stations, designed to detect ultra-high-energy (UHE) neutrinos interacting in the ice in Greenland. RNO-G is designed to detect the radio signal from Askaryan radiation produced by UHE neutrinos (either astrophysical or cosmogenic in origin) when they interact in the ice sheet. Neutrinos are...
The Radar Echo Telescope (RET) experiment aims to probe the >PeV cosmic neutrino flux with radar, targeting ionisation trails left in the wake of in-ice neutrino-induced cascades. The current focus of the RET collaboration is the Radar Echo Telescope for Cosmic Rays (RET-CR), a pathfinder experiment that utilised secondary in-ice particle cascades - produced by high-energy cosmic ray air...
The Radar Echo Telescope for Neutrinos (RET-N) is a future neutrino experiment that aims to observe the cosmic neutrino flux at the highest energies ($> 10^{16}$ eV) utilising radar. Radar allows for determining the position, speed and direction of any radio-reflecting object. High-energy neutrino interactions in glacial ice induce a particle cascade of energetic secondary particles, which in...
The Trinity Neutrino Observatory is designed to detect tau neutrinos in the 1 PeVโ10 EeV range by observing Cherenkov emission from extensive air showers following the decay of a tau emerging from the Earth. By bridging the gap between water/ice optical Cherenkov detectors and radio-based experiments, Trinity probes the poorly explored transition region between astrophysical and cosmogenic...
To maximise the Trinity Observatoryโs discovery potential for PeV-EeV tau neutrinos, identifying prime multi-messenger point sources is critical. X-ray bright and Compton-thick obscured AGN are compelling candidates; their dense environments drive efficient photohadronic neutrino production while attenuating gamma rays via pair production, making X-ray emission a vital diagnostic.
In...
While IceCube has measured the flux of astrophysical neutrinos at energies up to several PeV, much remains to be learned about its origin and nature. Tackling these questions will require a new generation of novel observatory designs. TAMBO, the Tau Air Shower Mountain-Based Observatory, will comprise an array of 5,000 plastic scintillator detectors deployed along the face of a wide, steep...
