Recent Progress on Hyper-Kamiokande Project Tetsuro Sekiguchi - PowerPoint PPT Presentation

Recent Progress on Hyper-Kamiokande Project Tetsuro Sekiguchi KEK, IPNS 2016. 5. 13 International Symposium on Revealing the history of the universe with underground particle and nuclear research 2016

2016/05/13 Koshiba Hall, University of Tokyo Contents 2 1. Overview 2. Physics 3. Recent progress 4. Summary

2016/05/13 Koshiba Hall, University of Tokyo Contents 3 1. Overview 2. Physics 3. Recent progress 4. Summary

2016/05/13 Koshiba Hall, University of Tokyo Hyper-Kamiokande 4 • Next generation water cherenkov detector • Multi-purpose detector for various physics

2016/05/13 Koshiba Hall, University of Tokyo Hyper-Kamiokande 5 To realize, are necessary • Next generation water cherenkov detector • Multi-purpose detector for various physics • Cost reduction • Internationalization

2016/05/13 Koshiba Hall, University of Tokyo New Photo-Sensor • Single-photon efficiency: x2 • 1 p.e. timing resolution: 2ns → 1ns • 1 p.e. charge resolution: 53% → 35% sensitivity 6 • New 20-inch photo-sensors: higher performance • Large impact on detector performance/physics

2016/05/13 Design Optimization • Total volume: 260kton/tank, Fiducial volume: 190kton/tank • In this talk, assume 2nd tank operation starts from 7th year after 1st tank operation. 7 Koshiba Hall, University of Tokyo Water Room Water Room Access Tunnel Access Tunnel Water Room Water Room Access Tunnel Access Tunnel Height 78m Height 78m Water Depth 60m Water Depth 60m Diameter 74m Diameter 74m • SK-like cylindrical vertical tank: Φ74m x H60m • Photo-coverage = 40% → 40k ID PMTs/6.7k OD PMT • 2 tanks with staging (1 tank at day1)

2016/05/13 Koshiba Hall, University of Tokyo Contents 8 1. Overview 2. Physics 3. Recent progress 4. Summary

2016/05/13 Day/night asym. in solar ν Supernova relic ν • Supernova burst ν • Supernova ν • p → e + π 0 (SK 90% limit = 1.7x10 34 y) • Proton decay → test of GUT • • Koshiba Hall, University of Tokyo θ 23 = 45°?, < 45°?, > 45°? • Mass hierarchy • CP violation • Neutrino oscillation (acc. ν, atom. ν, solar ν) • Physics at Hyper-K 9 • Rich physics topics!

2016/05/13 the universe. e.g. Petrov 1504.02402v1 • S. Pascoli et al., PRD 75, 083511 (2007) PDG review 2014 • Koshiba Hall, University of Tokyo 10 Need other CPV source to explain the matter-antimatter asymmetry in • The only known CPV source = CKM phase • Why ν CPV is important? • Leptonic (ν) CPV search is very important • Leptogenesis scenario only with Dirac CP phase • |sinδ CP |>~0.6 • Flavor symmetry prediction on δ CP • Precise measurement is also important!

2016/05/13 Koshiba Hall, University of Tokyo Measurement of CP Asymmetry with ν Beam • Max. ~±25% difference from δ=0 case • Sensitive to exotic (non-MNS) CPV source ＿ ＿ 11 • Comparison of P(ν μ →ν e ) and P(ν μ →ν e )

2016/05/13 14 ppp, 1.3s cycle) 12 14 ppp, 1.16s cycle Koshiba Hall, University of Tokyo Conventional neutrino beam from pion decay J-PARC Neutrino Beam Oscillation Maximum Decay Pipe Focusing Proton Target µ Devices Beam ν µ π • High intensity beam • 30 GeV, 750 kW proton beam (2x10 • Off-axis beam (2~2.5°) • 99% ν μ purity • Low energy narrow-band beam ~ 0.6 GeV • peak at 1st osc. max. with L=300km. • Future beam power upgrade • Aim to achieve 1.3 MW by 2026 • 3.2x10 • Great impact on HK LBL measurements

2016/05/13 Koshiba Hall, University of Tokyo CPV Sensitivity • >8σ(6σ) for δ=-90°(-45°) • ~80% coverage of δ parameter space with >3σ • 7~21° precision 13 Old 2tank • Exclusion of sinδ CP =0 • δ CP measurement precision

2016/05/13 • p→e + π 0 signal (10 years) Free proton decay ( 1 H) Bound proton decay ( 16 O) 14 Search for Proton Decay Free proton in hydrogen atom ↔ bound proton in 16 O Good PID and efficiency @ 1GeV Koshiba Hall, University of Tokyo • All decay products are visible. • Water cherenkov detector has advantages for this mode • Atm. ν bkg (10 years) Mediated by gauge bosons • Proton decay = direct observation of GUT • p→e + π 0 : leading decay mode in many models

2016/05/13 0 < p tot < 100 MeV/c ~9σ discovery potential ! Old New Invariant Mass (MeV/c) Invariant Mass (MeV/c) BKG Signal Signal τ proton =1.7x10 34 y (SK 90% CL limit) Koshiba Hall, University of Tokyo 0 < p tot < 100 MeV/c τ proton =1.7x10 34 y (SK 90% CL limit) Old, 10 years New (2tank), 10years 15 higher photo-coverage (40%) S/N improvement for Proton Decay (in case of τ proton = 1.7x10 34 years: SK 90% CL limit) • BKG reduced to ~1/5 thanks to • No reduction in signal eff.

2016/05/13 • Old New (2tank) 90% CL limit 3σ discovery sensitivity 16 90% CL limit: New(2tank) ~ old 3σ discovery sensitivity: New(1tank) ~ old Koshiba Hall, University of Tokyo • fiducial volume. 35 years Proton Decay Sensitivity New (1tank) • 3σ discovery can be achieved within 15 years if lifetime=1x10 • Higher photo-coverage (40%) gives better sensitivity even with smaller

2016/05/13 Koshiba Hall, University of Tokyo Supernova Burst Neutrinos • Inverse beta decay (ν e +p→n+e + ): 98k~136k evt. → isotopic • ν e +e - scattering: 4k~5k evt. → directional information • ν e from neutronization: 12~80 evt. → SN explosion mechanism • Property of neutrino: absolute mass, mass hierarchy ＿ 17 ν e scat. IBD • 100k~160k ν events from SN at 10kpc → very rich info.

2016/05/13 18 SRN candidate events SRN spectrum (10 years) New(1tank) New(2tank) Old New(1tank) New(2tank) Old years Koshiba Hall, University of Tokyo neutron-tagging efficiency 2 /s (>17.5MeV) 17 ) SNs occurred in the past universe Search for Supernova Relic Neutrinos SRN discovery sensitivity • O (10 • Expected flux: 0.3~1.5 evt/cm • Background: spallation, atm. ν • Higher photo-coverage helps to increase • 4.8σ discovery sensitivity expected after 10

2016/05/13 Koshiba Hall, University of Tokyo Contents 19 1. Overview 2. Physics 3. Recent progress 4. Summary

2016/05/13 Koshiba Hall, University of Tokyo HK Proto-Collaboration • ~250 members from 13 countries U-Tokyo and IPNS/KEK (2015. Jan.) 20 • HK proto-collaboration formed (2015. Jan.) • MoU for cooperation in HK project between ICRR/

2016/05/13 Texas 11” PMT by ETL (for OD) Intermediate detector @ 1~2km • Upgrade in near detector @ 280m • Near detectors • Electronics, DAQ, and so on. • • Koshiba Hall, University of Tokyo Multi-PMT module (for ID/OD) • Half of photo-sensors • Cavern, tank, half of photo-sensors • International Contribution 21 • Japanese contribution • Foreign contribution

2016/05/13 Koshiba Hall, University of Tokyo construction directors soon HKAC report will be submitted to the • U-Tokyo 22 English) HK Design Review • HK Design Report • Physics, detector, cost, organization, etc. (in • Cavern and tank design (in Japanese) • Hyper-Kamiokande Advisory Committee • Formed under directors of IPNS/KEK and ICRR/ • Main committee → review the HK Design Report • Sub-committee → review cavern and tank

2016/05/13 Koshiba Hall, University of Tokyo Timeline (1st Tank) • CPV study • Atm･Solar･Supernova ν study, Proton decay searches • Timely budget allocation is very important for international competition!! 23 • 2018~2025: Construction • 2026~ : Operation

2016/05/13 Koshiba Hall, University of Tokyo 2026. 24 Summary • Hyper-Kamiokande • Next generation water cherenkov neutrino & nucleon decay detector. • Design optimization • Vertical cylindrical shape (Φ74m x H60m) → 26kton/tank • 2 tanks with stating (to start as early as possible) • Many physics topics can be studied. • Discovery of CPV → Precise measurement • Search for Proton decay • Detection of astrophysical neutrinos (Solar ν, SN, SRN) • Recent progress • Porto-Collaboration, Design report, Review committee, submission to SCJ. • We are aiming to realize HK project and to start operation from