Hiroyuki Sekiya ICHEP2012 Jul 5 The Hyper-Kamiokande Experiment -Neutrino Physics Potentials- ICHEP2012 July Hiroyuki Sekiya ICRR, University of Tokyo for the Hyper-K Working Group

Hiroyuki Sekiya ICHEP2012 Jul 5 Let’s answer remaining questions! can reach all of them Using both accelerator and atmospheric s PMNS framework x Through the oscillation Majorana phase mass hierarchy Dirac CP phase  octant of  23 matter potential 2

Hiroyuki Sekiya ICHEP2012 Jul 5 Kamioka 3 rd Generation 1Mt Water Cherenkov Detector 39.3m 41.4m 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” ID 20% photo-coverage with 99,000 20” PMTs OD 2m layer with 25,000 8” PMTs Fiducial vol.0.56Mt Fiducial vol Mt SK x 25 3

Hiroyuki Sekiya ICHEP2012 Jul 5 The channel  → e,  → e L=295km, =2.6g/cm 3 case (assuming IH, =/2) neutrinoAnti-neutrino __ Leading sin 2 2 13 CPC CPV Solar matter Oscillation term Measured angles 4

Hiroyuki Sekiya ICHEP2012 Jul 5 Well established e- separation The Cherenkov method 5 Separation power Particle identification of e and μ Multi GeV 1 ring sample -like e-like blurred edge ring sharp edge ring ex) Super-Kamiokande IV

Hiroyuki Sekiya ICHEP2012 Jul o off-axis high intensity beam Accelerator from J-PARC J-PARC 30GeV proton beam power will be upgrade to 0.75MW 6 HyperK SuperK 295km J-PARC ~0.6GeV  cite candidates in Kamioka 2700mwe 1750mwe

Hiroyuki Sekiya ICHEP2012 Jul 5 Expected spectrum (dependence) Full MC (beam, interaction, detector, reconstruction) 7 Signal efficiency is 64%  CC BG rejection > 99.9%, NC  0 rejection >95% NH, sin 2 2 13 =0.1 mode 3.0 years mode 7.0 years _

Hiroyuki Sekiya ICHEP2012 Jul 5 Sensitivity to CP violation 10 years operation if MH is known by then 74% chance to observe CPV 8 5% systematic error is assumed. cf. Systematic error of T2K:10%    =0 exclusion (CPV sensitivity) in true  13 space Chance to observe CP violation >3 Fraction of  in  ] HK 5 year HK 10 year Run time  = 3:7 _ 0.75MWx10 years

Hiroyuki Sekiya ICHEP2012 Jul 5 10 years operation 43% chance to determine the MH. Sensitivity to Mass Hierarchy 9 Run time  = 3:7 _ 5% systematic error is assumed. “J-PARC+Hyper-K” only N.B. Do not multiply 43% bf 74%! MH sensitivity (IH exclusion for true NH case) in true  13 space 0.75MWx10 years

Hiroyuki Sekiya ICHEP2012 Jul 5 Atmospheric Free neutrino source Very long base line (in matter) Wide energy range cos= -1, L ～ ㎞ 10 E< ～ 1.3GeV e :  =1:2 Region of interest is Multi-GeV, upward(<0) cos = 1 L ～ 15 ㎞ cos 

Hiroyuki Sekiya ICHEP2012 Jul 5 Statistical PID Water Cherenkov detector can separate e from e statistically SK 4 data (448.6 days) Number of decay-e >0 e -like ex) Super-K IV Multi-GeV 1ring e-like CCnonQE interactions Number of decay-e =0 anti e -like MC e -like _ e -pulity 36.7% _ e -pulity 60.5% Number of decay-e _

Hiroyuki Sekiya ICHEP2012 Jul 5 Expected zenith angle distributions for N e /N 0 e (MH,  23 ) MH difference (btw solid and dashed )is clearly visible. 12 Multi-GeV e -like Multi-GeV anti- e -like Full MC

Hiroyuki Sekiya ICHEP2012 Jul 5 Sensitivity to Mass Hierarchy Significance ≡  2 for wrong MH assumption 13  2 for assuming Inverted Normal hierarchy case Inverted hierarchy case  2 for assuming Normal Hyper-K 10 years  sin 2  23 =0.6 sin 2  23 =0.5 sin 2  23 =0.4 sin 2  23 =0.6 sin 2  23 =0.5 sin 2  23 = years operation For most cases, MH is determined

Hiroyuki Sekiya ICHEP2012 Jul 5 Sensitivity to  23 octant 14 sin 2 2 23 =0.96 case sin 2  23 =0.4 or 0.6 sin 2 2 23 =0.99 case sin 2 q 23 =0.45 or 0.55 Hyper-K 10 years NH 90%CL Hyper-K 10 years NH 90%CL : assumed true parameter 10 years operation Could be discriminated even for sin 2 2 23 =0.99

Hiroyuki Sekiya ICHEP2012 Jul 5 Other Physics Topics Nucleon decay search 15 Solar neutrino Neutrino geophysics WIMP search Supernova burst neutrino Supernova relic neutrino (DSNB) Gd load option

Hiroyuki Sekiya ICHEP2012 Jul 5 Technical R&D Large cavern excavation 16 Water tank Photo sensor ◦8 inch HPD is in testing ◦20 inch HPD is under development Hamamatsu Photo tube (cathode) Water purification system electronics APD

Hiroyuki Sekiya ICHEP2012 Jul 5 Conclusion It’s time to start next generation detectors. A mega ton water Cherenkov detector, Hyper-Kamiokanade provides a very rich physics program. Can be realized with well- established technology. Open Hyper-K meeting will be held. 17 Open Hyper-K Meeting August 21-23, 2012 Kavli IPMU, Kashiwa, Japan All those interested are welcome to join the meeting!

Hiroyuki Sekiya ICHEP2012 Jul 5 Extra slides 18

Hiroyuki Sekiya ICHEP2012 Jul 5 Possible Schedule 19

Hiroyuki Sekiya ICHEP2012 Jul 5 Accelerator selection criteria 20 CCQE

Hiroyuki Sekiya ICHEP2012 Jul 5 BG e contamination in mode 21 _

Hiroyuki Sekiya ICHEP2012 Jul 5 MC Expected number of event mode 3 years 22 mode 7 years _

Hiroyuki Sekiya ICHEP2012 Jul 5 Accelerator  2 23 i : Energy bin index (per 50MeV) f X : systematic parameters N i : # of events for i-th bin with “true” set of parameters n i : # of events for i-th bin with “test” set of parameters σ X : systematic errors for corresponding f X (5% are assumed)

Hiroyuki Sekiya ICHEP2012 Jul 5 Expected allowed region Assuming true is (=/2, sin 2 2 13 =0.1 ) 24

Hiroyuki Sekiya ICHEP2012 Jul 5 IF MH is unknown Assuming true is (=/2, sin 2 2 13 =0.1 ) 25 Two degeneracy region

Hiroyuki Sekiya ICHEP2012 Jul 5  13 dependence of  measurement Too large  13 is not so helpful… 26

Hiroyuki Sekiya ICHEP2012 Jul 5 Atmospheric 3 flavor oscillation 27

Hiroyuki Sekiya ICHEP2012 Jul 5 Atmospheric MSW resonance e for NH, e for IH 28 _

Hiroyuki Sekiya ICHEP2012 Jul 5 Statistical PID Multi-ring case: Liklihood method 29

Hiroyuki Sekiya ICHEP2012 Jul 5 Statistical PID 30

Hiroyuki Sekiya ICHEP2012 Jul 5 MC Expected number of e -like, e -like 31 _

Hiroyuki Sekiya ICHEP2012 Jul 5 32 Atmospheric  2

Hiroyuki Sekiya ICHEP2012 Jul 5 Expected zenith angle distributions for N e /N 0 e ()  difference is visible. 33 Multi-GeV e -like Multi-GeV anti- e -like Full MC

Hiroyuki Sekiya ICHEP2012 Jul 5 34 Sensitivity to  atmospheric by itself

Hiroyuki Sekiya ICHEP2012 Jul 5 Super-K atmospheric event categories 35