The Hyper-Kamiokande Experiment

The Hyper-Kamiokande Experiment Sammy Valder On behalf of the Hyper-Kamiokande Collaboration XXI Workshop on Neutrino Telescopes 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 2 Kamioka Water Cherenkov Experiments KamiokaNDE (1983-1996) •3 kton •Atmospheric and solar neutrino “anomaly” •SN1987A •Nobel Prize: detection of cosmic neutrinos Super-KamiokaNDE (1996-onwards) •50 kton (22.5 kton FV) •Best limits for proton decay •T2K far detector •Nobel Prize: discovery of neutrino oscillations Hyper-KamiokaNDE (~2028-onwards) •260 kton (188 kton FV) •Nobel Prize: ??? 41.4 m 39.3 m 71 m 68 m 2002 2015 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 3 The Hyper-Kamiokande Collaboration •~650 members from 106 institutions in 22 countries as of December 2024 and still growing…! •Hosted by University of Tokyo & KEK/J-PARC 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 4 The Physics Sources Atmospheric neutrinos: 𝜈𝜇 , 𝜈e , 𝜈𝜇 , 𝜈e Solar neutrinos: 𝜈e High energy neutrinos Supernova burst neutrinos Diffuse supernova neutrino background Proton decay J-PARC neutrino beam: 𝜈𝜇 , 𝜈𝜇 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 5 The Hyper-Kamiokande Project Hyper-Kamiokande (Far Detector) Intermediate Detector Near Detector Complex INGRID ND280 J-PARC TOKAI KAMIOKA TOKYO 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 6 J-PARC Beam Upgrades •Continuous increase from 0.5 MW (2019) to 1.3 MW (2028) → Already above 0.8 MW •Upgrades: •Cycle time: 2.48 s → 1.16 s (Already reduced to 1.32 s) •Protons per pulse: 2.6 x 1014 → 3.3 x 1014 •Beam optics improvements •J-PARC neutrino beam to be used by T2K until the start of HK 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 7 Near Detector Complex On-axis Detector •INGRID •Monitors neutrino beam stability and profile (direction + event rate) Off-axis Magnetized Tracker •ND280 •2.5° off-axis •Measure the neutrino interactions (cross-sections) and energy spectrum before oscillations occur •Upgraded by T2K to include SuperFGD + High Angle TPCs •Further upgrades planned for Hyper-Kamiokande Situated 280 m from beam source 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 8 (NEW) Intermediate Detector: IWCD ~ 50 m C. Naseby and the Hyper-Kamiokande Collaboration 2021 J. Phys.: Conf. Ser. 2156 012121 multi-PMT module Situated 850 m from beam source ~8 m ~7 m •Vertically movable water Cherenkov detector with 360 mPMTs. mPMTs have been operated long-term in WCTE and showed good performance. Systematically similar to far detector. •Measure ൗ 𝜎(𝜈𝑒) 𝜎(𝜈𝜇) 𝜎(ഥ 𝜈𝑒) 𝜎(ഥ 𝜈𝜇) with a 3% accuracy at 600 MeV to improve 𝛿CP sensitivity significantly •A linear combination of the results for different off-axis angles will allow neutrino interaction model independent knowledge of the neutrino energy •Facility construction has already begun. 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 9 Far Detector Inner detector (ID) •216 kton (188 kton Fiducial Volume) •20,000 50 cm improved PMTs to be installed •Twice better performance (photodetection efficiency, charge and time resolution) than SK PMTs •~800 mPMT modules integrated as a hybrid configuration •Improving Cherenkov ring reconstruction in detector corners •20% photocoverage Outer detector (OD) •1 m (2 m) thick for barrel (top/bottom end caps) •3600 3” PMTs + WLS plates •Walls are covered in highly-reflective Tyvek sheets Situated 295 km from beam source 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 16 High Energy Astrophysical Neutrinos Fully Contained (FC) Partially Contained (PC) Throughgoing Upgoing muon (Up-mu) Super-Kamiokande Hyper-Kamiokande (sensitivity) Super-K event rates •Hyper-K is opportunistically situated in a ”gap” between accelerator neutrinos and neutrino telescopes •~1000 events per year in the TeV region from upgoing muon sample •Rich TeV scale physics: prompt neutrinos, galactic plane neutrinos, etc. Preliminary 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 17 Hyper-Kamiokande Timeline 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 18 Detector Construction •The cavern has now been fully excavated (July 2025) •The main cavern is one of the largest single volumes ever excavated •~15,000 (out of 20,000) PMTs delivered •Screening/signal QA checks at Kamioka in 2 dark rooms (100 PMTs ea.) •Tests of underwater electronics underway in Kamioka & CERN 02/10/2025 The Hyper-Kamiokande Experiment - NeuTel 2025 19 Summary & Conclusions •Hyper-Kamiokande is a next generation experiment in Japan: •New, massive, ~260 kton water Cherenkov far detector •Upgraded J-PARC 1.3 MW neutrino beam •Upgraded near detectors •New Intermediate Water Cherenkov Detector •Construction started in 2020, cavern is now fully excavated, operation scheduled to begin in 2028 •Wide and ambitious physics program from a variety of sources, including but not limited to: •J-PARC beam neutrinos •Solar neutrinos •Atmospheric neutrinos •Supernova neutrinos •High energy astrophysical neutrinos •Proton decay searches Hyper-K poster: Camilla Forza – Testing underwater PMT units under pressure Other talks: T2K experiment – Sophie King (Tuesday) Super-K experiment – Lucas Machado (Tuesday) Backups