1 Super Beams Takashi Kobayashi IPNS, KEK  ’04 June 17, 2004 Paris Contents 1.Introduction 2.“Super beam” experiments 3.Summary Future dream for 10~20years from now

2 Conventional neutrino beam with (Multi-)MW proton beam (  Fact) Pure  beam ( ≳ 99%) e ( ≲ 1%) from     e chain and K decay(Ke3)    can be switched by flipping polarity of focusing device What is (Original) Super Beam? Proton Beam Target Focusing Devices Decay Pipe Beam Dump  ,K,K  Strongly motivated by high precision LBL osc. exp.

3 Long baseline osc. experiments 1 st phase experiments (Now) 1 st phase experiments (Now) Confirmation of atm. results Confirmation of atm. results K2K(1999~)/MINOS(2005~)/ICARUS/OPERA(2006~) K2K(1999~)/MINOS(2005~)/ICARUS/OPERA(2006~) 2 nd phase experiments (Now~10yrs) 2 nd phase experiments (Now~10yrs) Discovery of e appearance Discovery of e appearance Designed & Optimized aft. SK atm Designed & Optimized aft. SK atm ~MW beam w/ ~50kton detector ~MW beam w/ ~50kton detector T2K-I (approved. 2009~)/NO A (2009?~) / (C2GT) T2K-I (approved. 2009~)/NO A (2009?~) / (C2GT) 3 rd phase experiments(10~20yrs?) 3 rd phase experiments(10~20yrs?) CP violation and mass hierarchy thru   e app. CP violation and mass hierarchy thru   e app. Typically Multi-MW beam & Mton detector Typically Multi-MW beam & Mton detector 2 nd phase is critical step to go 2 nd phase is critical step to go Classification by “ Super Beam ” Experiments ()() ()()

4   e appearance & CPV   e appearance & CPV   , a  -a for Matter eff.: CP-odd Solar Main Matter # of signal ∝ sin 2  13 (Stat err ∝ sin  13 ), CP-odd term ∝ sin  13 Sensitivity indep. from  13 (if no BG & no syst. err)

5 CPV vs matter effect 295km730km Smaller distance/lower energy  small matter effect Pure CPV & Less sensitivity on sign of  m 2 Combination of diff. E&L help to solve.   e osc. probability w/ 2 2  13 =0.01

6 High intensity narrow band beam -- Off-axis (OA) beam -- (ref.: BNL-E889 Proposal)  Target Horns Decay Pipe Far Det. Decay Kinematics  Increase osc. max.  Decrease background from HE tail 1/~1/~ E  (GeV) E (GeV)  flux

7 Idea of C2GT (CNGS to Gulf of Taranto) OA-CNGS OA-CNGS Movable underwater Cherenkov det. (r=150m), 2Mt fid vol, L=1,200~1,600km Movable underwater Cherenkov det. (r=150m), 2Mt fid vol, L=1,200~1,600km ~5,000  CC/year ~5,000  CC/year Disappearance & Appearance Disappearance & Appearance sin 2 2  13 sin 2 2  13 Technology to be established (underwater, light collection, LE PID, … ) Technology to be established (underwater, light collection, LE PID, … ) F.Dydak et.al. E  GeV) Flux (m -2 )  e 1

8 Kamioka J-PARC (Tokai-mura)T2K-II (0.75MW  )4MW 50GeV J-PARC (0.75MW  )4MW 50GeV J-PARC OA 2~3deg OA 2~3deg E peak=0.5 ~0.8GeV E peak=0.5 ~0.8GeV L=295km L=295km Hyper Kamiokande Hyper Kamiokande ~360k  CC/yr ~360k  CC/yr  13, CPV  13, CPV Small matter effect Small matter effect OAB2.0deg OAB2.5deg OAB3.0deg

9 J-PARC (Japan Proton Accelerator Research Complex) Linac 3GeV PS 50GeV PS (0.75MW) N FD Neutrino Beam Line To SK Pacific Ocean (formerly known as JHF) Construction: 2001~2007 Construction: 2001~ MW 50GeV-PS 0.75MW 50GeV-PS Possible upgrade to 4MW Possible upgrade to 4MW Preliminary study done Preliminary study done Rep. rate x 2.5 Rep. rate x 2.5 Double RF cavities (space OK) Double RF cavities (space OK) Eliminate idling time in acc. cycle Eliminate idling time in acc. cycle Double # of circulating protons Double # of circulating protons “ barrier bucket method ” to avoid space charge limit “ barrier bucket method ” to avoid space charge limit Issues Issues Achieve first goal (0.75MW) Achieve first goal (0.75MW) Beam loss Beam loss Target, … Target, … (these apply also for other projects)

10 J-PARC December, 2003 Tokai-village December, 2003

11 2 detectors×48m × 50m ×250m, Total mass = 1 Mton Far Detector: Hyper-Kamiokande

T.Kobayashi (KEK) 12 Sensitivity for  13 sin 2 2  13 ~0.006 (90%) sin 2 2  13 < can be searched if syst err ~ few % 0.5xsin 2 2  13 sin 2 2  13 ~0.018 (3  )

13 / CC interaction spectrum for CPV meas. / CC interaction spectrum for CPV meas.   Wrong sign BG (x10   case) cross section difference N CC (/100MeV/22.5kt/year)  : 2 years  : 6.8 years

14 sin 2 2  13 =0.02 Very Preliminary Expected signal and BG (SK full sim) signalbackground  =0  =  /2 total   e e   e   e  m 21 2 =6.9x10 -5 eV 2  m 32 2 =2.8x10 -3 eV 2  12 =0.594  23 =  /4  13 =0.05 (sin 2 2  13 =0.01)  :2yr,  :6.8yr 4MW 0.54Mt

T.Kobayashi (KEK) 15 Sensitivity for CPV in T2K-II no BG signal stat only (signal+BG) stat only stat+2%syst. stat+5%syst. stat+10%syst. CHOOZ excluded sin 2 2  13  m 31 2 ~3x10 -3 eV 2 T2K 3  discovery 3  CP sensitivity : |  |>20 o for sin 2 2  13 >0.01 with 2% syst. 4MW, 540kt 2yr for  6~7yr for   m 21 2 =6.9x10 -5 eV 2  m 32 2 =2.8x10 -3 eV 2  12 =0.594  23 =  /4 T2K-I 90%

16 Europe: SPL  Frejus Geneve Italy 130km 40kt  400kt 4MW 2.2GeV Superconducting Proton Linac CERN 4MW 2.2GeV Superconducting Proton Linac CERN Low energy wide band (E ~0.3GeV) Low energy wide band (E ~0.3GeV) L=130km L=130km Water Cherenkov 40  400kt (UNO) Water Cherenkov 40  400kt (UNO) ~18,000  CC/year/400kt ~18,000  CC/year/400kt  13, CPV  13, CPV Small matter effect Small matter effect SPL in R&D, UNO in conceptual design SPL in R&D, UNO in conceptual design

17 Mezzetto Fluxes for SPL beam Low energy wide band beam Low energy wide band beam Less NC  0 BG for e search Less NC  0 BG for e search

18  13   Sensitivity for CPV sin 2 2  13 =0.03  13 (deg) 2 5  (deg)

19BNL-Homestake 28GeV AGS upgrade to 1MW (2MW) cf current 0.1MW 28GeV AGS upgrade to 1MW (2MW) cf current 0.1MW Wide band beam (0.5~6GeV) Wide band beam (0.5~6GeV) L=2,540km L=2,540km Mton UNO (alternative option: Liq. Ar.) Mton UNO (alternative option: Liq. Ar.) ~13,000  CC/year/500kt ~13,000  CC/year/500kt Cover higher osc. maxima Cover higher osc. maximaGoals e appearance e appearance Sign of  m 23 Sign of  m 23 CPV CPV  12,  m 12  12,  m 12 Possible w/ only run at certain parameter region (Ref: Diwan et al., PRD68, , 2003) 2540 km Homestake BNL

Page 20 S. Holmes, Mulit-MW Workshop, May 2004 Brookhaven AGS Upgrade Direct injection of ~ 1  protons via a 1.2 GeV sc linac extension –low beam loss at injection; high repetition rate possible –further upgrade to 1.5 GeV and 2  protons per pulse possible (x 2) 2.5 Hz AGS repetition rate –triple existing main magnet power supply and magnet current feeds –double rf power and accelerating gradient –further upgrade to 5 Hz possible (x 2)

21 Detector options: UNO (or Liq. Ar?) Highway tunnel Detector Perlite insulation h =20 m  ≈70 m Electronic crates A. Rubbia C.K.Jung 440kton fiducial mass A.Rubbia ~100kton

22 Mass Hierarchy Resolution w/ only running, reversed hierarchy rejected >2.5  level w/ only running, reversed hierarchy rejected >2.5  level with w/ / running, then >10  with w/ / running, then >10  Diwan, Mar.2004

23 Sensitivity on CPV Diwan, Mar.2004

24 Fermilab Proton Driver (PD) 8 GeV synchrotron option Original concept (May 2002, Fermilab-TM-2169) Original concept (May 2002, Fermilab-TM-2169) Large aparture (100x150mm) magnets Large aparture (100x150mm) magnets LINAC 400MeV  600MeV LINAC 400MeV  600MeV MI cycle time 1.87s  1.53s MI cycle time 1.87s  1.53s  Net results : MI power of 1.9MW 8 GeV superconducting linac Recent study Recent study Direct injection Direct injection 8GeV & 40~120GeV(MI) 8GeV & 40~120GeV(MI) Future flexibility Future flexibility Issue: Cost? Issue: Cost? Replace injector for Main Injector Increase MI power by x5~6 (2MW)  Improve MINOS & NO A sensitivities

25 ~ 700m Active Length 2 MW 8 GeV Linac X-RAY FEL LAB Slow-Pulse Spallation Source & Neutrino Target Neutrino “Super- Beams” Main MW 8 GeV NUMI Anti- Proton SY-120 Fixed- Target Off- Axis Also includes upgrades to Main Injector for current and cycle To Homestake 120 GeV and 8 Gev Potential Flexibility of LINAC B.Foster and D.Michael, BNL-APS SB WS Mar.04

26 NO A + PD : Mass hierarchy G.Feldman Jun.04

27 Homestake BNL Henderson Mine Fermilab ~8m ~200M ~4m 30 mR maximum off axis 120 GeV protaons 8 GeV protons Another possibility with PD 1290km A case study for future experiment with PD A case study for future experiment with PD 2MW 8/120GeV PD  “ 4MW ” 2MW 8/120GeV PD  “ 4MW ” WB/OA to (or Henderson) WB/OA to (or Henderson) E =0.5~3GeV E =0.5~3GeV Cover higher osc max Cover higher osc max 500kt WC or 100kt Liq.Ar 500kt WC or 100kt Liq.Ar ~50k  CC/year/500kt ~50k  CC/year/500kt Studies of physics potential started Studies of physics potential started FeHo (Fermilab-Homestake) Beam Line D.Michael 5yrs

28 Sensitivities with 500kt Water C D.Michael May 04, FNAL  (  m 2 )<1%  (sin 2 2  )~4% (90%) Disappearance Appearance 100kt Liq Ar could be better thanks to det. resolution Studies in progress. 5yrs running

29 Summary of ( “ super-beam ” ) LBL experiments E p (GeV)Power(MW) Bea m 〈 E 〉 (GeV)L(km) M det (kt)  CC  CC(/yr) K2K WB ~50~1% MINOS(LE)1200.4WB ~2,5001.2% CNGS4000.3WB18732~2~5,0000.8% T2K-I500.75OA ~3,0000.2% NO A OA~2810?50~4,6000.3% C2GT4000.3OA0.8~12001,000?~5,0000.2% T2K-II504OA0.7295~500~360,0000.2% NO A+PD 1202OA~2810?50?~23,0000.3% BNL-Hs281WB/OA~12540~500~13,000 SPL-Frejus2.24WB ~500~18,0000.4% FeHo8/120 “4”“4”“4”“4”WB/OA1~31290~500~50,000 Running, constructing or approved experiments I II III

x  m 2 (L/E) [  /2] T2K-II K2K MINOS CNGS NO A T2K-I C2GT NO A+PD BNL-Hs (<5  ) SPL-Frejus 13 5 osc. maxima BNL-Hs C2GT NO A MINOS CNGS T2K K2K SPL-Frejus “ Graphical ” Summary of experiments  m 2 =2.5x10 -3 eV 2 <30GeV FeHo FeHo <10yrs 10~20yrs <5yrs

31Summary Next generation “ Super Beam ” experiments will provide chances to clarify whole view of mixing Next generation “ Super Beam ” experiments will provide chances to clarify whole view of mixing  13  13 CPV, sign of  m 2,.. CPV, sign of  m 2,.. High precision measurements of parameters High precision measurements of parameters Several experiments are under consideration Several experiments are under consideration (Multi-)MW beam + Mton detector (or Liq.Ar) (Multi-)MW beam + Mton detector (or Liq.Ar) Japan: 4MW J-PARC  Mt Hyper-Kamiokande Japan: 4MW J-PARC  Mt Hyper-Kamiokande Europe: 4MW 2.2GeV SPL  Mt UNO Europe: 4MW 2.2GeV SPL  Mt UNO US-BNL: 1(2)MW AGS  US-BNL: 1(2)MW AGS  US-FNAL: 2MW PD/MI  NO A/ US-FNAL: 2MW PD/MI  NO A/ Future direction much depend on results from “ 2 nd phase ” experiments Future direction much depend on results from “ 2 nd phase ” experiments T2K-I(2009~) and NO A(if approved) T2K-I(2009~) and NO A(if approved) Let ’ s do experiments to know  13 (2 nd phase) ASAP!!, Let ’ s do experiments to know  13 (2 nd phase) ASAP!!, While keeping R&D efforts for future projects While keeping R&D efforts for future projects (while reducing too many meeting!) (while reducing too many meeting!)