The Hyper-K Working Group Hyper-Kam iokande Project I ts Physics Potential Astroparticle Physics 2014 Hiroyuki Sekiya ICRR, University of Tokyo for the Hyper-K Working Group 1 Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam
Rem aining issues for Neutrino mixing parameters ◦ CP phase δ , Mass hierarchy| m 32 2 | , octant of θ 23 Neutrinos as “astroparticles” ◦ Solar neutrinos Spectrum upturn(Solar matter effects, sterile?) Day/ night asymmetry (Earth matter effect) ◦ Supernovae neutrinos Galaxy Atmosphere Sun Burst(mechanism of SN) DSNB(history of Universe) Supernovae ◦ High energy neutrinos from GC, Sun, earth… Dark matter Proton decay J-Parc All of them are statistically limited! Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 2
Let’s m ove on to “m ore than Super” Atmosphere Sun Galaxy Supernovae J-Parc Hyper- (Wikipedia) A prefix often used in scientific and technical words, to denote something above or beyond the usual, normal, expected, or healthy level. Sometimes used to mean extreme or specifically "more than super-". Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 3
Kam ioka 3 rd Generation 1 Mt W ater Cherenkov Detector Fiducial vol.0.56Mt Fiducial vol. 0.0225Mt 2 cylindrical tanks lying side-by-side (48m x 54m x 250m each) 5 compartments in each tank w/ photo-sensitive separation walls Each compartment is “twice the size of Super-Kamiokande II” I D 20% photo-coverage with 99,000 20” PMTs For solar neutrinos OD 2m layer with 25,000 8” PMTs PMT must be doubled Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 4
Neutrino m ixing param eters Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 5
Status of ν m ixing param eters Recent results from T2K & reactor ν e appearance +0.038 (NH) 0.140 − 0.032 T2K sin 2 2 θ 13 = +0.044 (IH) 0.170 − 0.037 is slightly larger than the ones from reactor experiments → indication of non-zero δ cp ❓ The best overlap is for the Normal hierarchy with δ cp = – π / 2! c.f. Daya Bay Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 6
_ _ The channel ν µ → ν e , ν µ → ν e Oscillation term Leading sin 2 2 θ 13 CPC Measured angles CPV Solar matter L= 295km , ρ = 2.6g/ cm 3 case (assuming NH, δ = - π / 2) neutrino Anti-neutrino Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 7
w ith J-PARC ν beam _ 2 .5 o off-axis narrow band ν beam ν mode ν mode J-PARC 30GeV proton beam power will be upgrade to ＞ 0.75MW ＞１ MW is under study cite candidates in Kamioka SuperK ~ 0.6GeV ν µ 2700mwe 2 9 5 km 1750mwe Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 8
expected spectra ( δ dependence) Full MC based on T2K experience beam BG , ν interaction, detector, reconstruction NH, sin 2 2 θ 13 = 0.1, sin 2 2 θ 23 =1.0 Total 7.5 x 10 7 MW·sec (10 years) _ ν mode 2.5 years ν mode 7.5 years Expected number of events δ = 0 WC PID is excellent → ν µ CC BG rejection > 99.9% • π 0 rejection is established → NC π 0 is no longer dominant BG! • Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 9
sensitivity to δ CP Use both reconstructed energy spectra and number of observed events 90% CL allowed regions for δ = -90 o , 0 o , 90 o , 180 o Normal hierarchy Inverted hierarchy Determination power of δ CP parameter: 1 σ error of δ CP is expected to be 8 o ~ 19 o . 10 Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 10
sensitivity to CPV sin δ =0 exclusion (CPV sensitivity) Chance(% ) to observe CP violation 7.5 x 10 7 MW·sec (10 years) Fraction of δ in [−π,π ] Normal hierarchy 76% chance to observe CPV at 3 σ 58% chance to observe CPV at 5 σ Mass hierarchy is assumed to be known Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 11
MH? atm ospheric ν! cos Θ = 1 L ～ 1 5 ㎞ ν e appearance probability core _ cos Θ = -1 , L ～ 1 3 00 0 ㎞ Region of interest: Multi-GeV, upward( Θ < 0) ν μ → ν e resonance occurs in earth’s core. _ It is either ν e or ν e depending on MH Not only MH, but also has sensitivity to • θ 23 octant • CP asymmetry Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 12
expected zenith angle distributions for N e / N 0 e ( MH, θ 2 3 dependence) Multi-GeV ν e -like 10 years Full MC MH difference (and θ 23 octant difference) are clearly visible. Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 13
sensitivity to MH sin 2 2 θ 13 =0.1 Significance ≡ ∆χ 2 for wrong MH rejection HK 10 years operation Band : range of CP ∆χ 2 for assuming Normal ∆χ 2 for assuming Inverted Inverted Hierarchy Normal Hierarchy Sensitivity depends on θ 23 , but for most cases MH can be determined > 3 σ Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 14
sensitivity to θ 2 3 octant sin 2 2 θ 13 =0.1 Significance ≡ ∆χ 2 for wrong octant rejection HK 10 years operation Band : range of CP Inverted Hierarchy Normal Hierarchy MH unknown MH unknown Octant can be determined > 3 σ if sin 2 θ 23 < 0.47 and sin 2 θ 23 > 0.53 for NM if sin 2 θ 23 < 0.45 and sin 2 θ 23 > 0.56 for IM Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 15
Astroparticle Neutrinos Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 16
sensitivity to SN burst ν SN in nearby galaxies Hyper-K detection probability Cumulative supernova rate No osc. E > 10 MeV NH Time window IH = 10sec. > 0.5 0.1 1 SN about every 10 years is expected within 2 Mpc. > 50% chance for signal multiplicity of 3 for SN at 2 Mpc SN in our galaxy Huge statistics ~250k events @ 10kpc Sensitive to MH Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 17
sensitivity to DSNB ( SN relic neutrino) Sensitivity depends on spallation BG by cosmic µ µ flux Elevation data in Kamioka SK Mozumi HK Mozumi HK Tochibora At Tochibora, SK x 4 spallation BG Expected DSNB spectra for various models LMA model significance SK spallation BG DSNB observation > 3 σ in 5 years > 5 σ in 10 years Adding Gd increases the significance years Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 18
W I MP annihilations Possible annihilation channels ◦ χχ → qq,gg,cc,ss,bb,tt,W + W - ,ZZ, τ + τ − , µµ,νν , e + e - , γγ Few neutrinos “high energy neutrinos” in decay Dominant decay into hadrons Charged pions decay producing neutrinos up to E=52.8MeV targets of usual indirect search “low energy neutrinos” Unique targets for SK/HK C.Rott et al., arXive: 1208.0827 Up-going ν µ effective area Hyper-K LOI arXiv 1109.3262 HK Fiducial vol.: 25 x SK HK Effective area: ~18 x SK sensitivity 3~6 x SK Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 19
sensitivity to W I MPs low energy ν In the Sun high energy ν Model the full hadronic shower in the Sun. WIMP-n spin-dependent Minimal dependence on channels. cross section (pb) Hyper-K 4yrs +Gd +factor 5 BG reduction bb Hyper-K 5yrs ττ Hyper-K 5yrs 100 1000 WIMP mass (GeV) In the Galaxy In low mass region Studies on Hyper-K Hyper-K will be the best! sensitivity are on going Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 20
sensitivity to proton decay 10 times better sensitivity than Super-K ◦ Only realistic plan to go beyond 10 35 years for p → e + π 0 In lucky case, 3 σ discovery is possible! Hyper-K 10years sensitivities to various modes p → e + π 0 1.3 x 10 35 years (90% CL) 5.7 x 10 34 years (3 σ discovery) p → ν K + SUSY favored 3.2 x 10 34 years (90% CL) 1.2 x 10 34 years (3 σ discovery) Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 21
Water purification system Technical R&D Water tank Large cavern excavation Photo sensor electronics ◦ High QE 20’’ BL-dynode PMTs and high QE 20’’ HPDs will be tested in water. APD Box & Line Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 22
Conclusion Hyper-K has great potential for wide range of Physics. ◦ Neutrino mixing parameters Discovery potential of CPV( δ CP ) for 76% of the region with 3σ . Determine Mass hierarchy and θ 23 octant with 3σ. ◦ Astrophysical neutrinos Burst Supernovae sensitivity N ν > 3 at 2Mpc SRN > 3 σ in 5 year w/ o Gd Best sensitivity to Low mass WI MPs ◦ Proton decay sensitivity o(10 35 )years for p → e + π 0 ◦ Other physics including unexpected ex. sterile/ ν mass: KOHRI ’s talk on Friday at 18: 10 Preparation works are in progress. Hyper-K is open to the international community. ◦ 5 th Open Hyper-K meeting in Vancouver July 19-22 at UBC/ TRIUMF Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 23
Extra slides Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 24
Tim eline Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 25
Political Hiroyuki Sekiya TeVPA+ I DM2 0 1 4 Jun 2 5 2 0 1 4 @Am sterdam 26
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