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Toward realistic evaluation of the T2KK physics potential

Toward realistic evaluation of the T2KK physics potential. What’s that ?. Preliminary. KEKPH0712 @ KEK Dec.12, 2007 N.Okamura (KEK). What’s the T2KK ??. There are 6 parameters in the “neutrino oscillation” Unknown parameters The sign of the larger mass-squared difference

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Toward realistic evaluation of the T2KK physics potential

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  1. Toward realistic evaluation of the T2KK physics potential What’s that ? Preliminary KEKPH0712 @ KEK Dec.12, 2007 N.Okamura (KEK)

  2. What’s the T2KK ?? • There are 6 parameters in the “neutrino oscillation” • Unknown parameters • The sign of the larger mass-squared difference • Value of the CP phase (MNS) • Value of the 13  Reactor exp. will measure • The correct value of 23 (larger or smaller than 45o) • T2KK = Tokai-to-Kamioka exp. (T2K, will start 2009) + far detector in Korea (L~1000km) • T2K neutrino beam will reach Korea, automatically.

  3. mass hierarchy CP phase 1 ~ 30o w/o anti-neutrino 2 = 22 (input : normal) Digest of our previous work essence of T2KK 2 detectors, 300km + 1000km matter effect helps to determine 2 of 3 (1acc.,2detector) exist • 5x1021POT exposure • include the “reactor exp.” • Volume 22.5 kton/100Kton (SK/Kr) • OAB : 3.0/0.5 (SK/Kr) sin22RCT=0.1, MNS=0.0 Detail of T2KK K.Hagiwara, K.Senda, NO, PLB637 266 (2006) PRD76 093002 (2007) K.Hagiwara, NO, hep-ph/0611058 and ref. there in

  4. motivation We study the robustness of the results, best combination, hierarchy (2), CP phase (MNS).

  5. CC • Reconstruction • Resolution • Fit functions

  6. (106):mono. energy E = 1GeV 25000 CCQE 20000 Res. 15000 10000 5000 Erec 400MeV total (CC) : 728702 CCQE : 390620 resonance : 129340 event selection • only one  (e) |p| > 200MeV • no high energy +/- |p| < 200MeV • no high energy  |p| < 30MeV • no 0/Ks/K+/K- nuance Ver.3.504 (Apr/25,2006) D. Casper (UC.Irvine)

  7. resolution Detector has the resolution for momentum and the angle. Dilute the reconstruction energy obtained from the momentum of e, and scatter angle. e :E=2GeV (from SK)

  8. fit functions For E  Erec conversion : fit function CCQE Res. • Sum of the 3 gauss functions for CCQE, 3 or 4 gauss functions for resonance mode. • Cover region : Erec > 0.4GeV for E=0.3 ~ 6.0GeV • Erec < 0.4GeV • rapid oscillation, small , etc. not include • E > 6.0GeV  no beam flux

  9. NC • 0 event (for e-like background)

  10. event selection • only one 0 • no- / e • no high energy +/- |p| < 200MeV • no high energy  |p| < 30MeV • no Ks/K+/K- • 0.5 OAB • 480 event at 0.2-0.4GeV • 300 event at 0.4-0.6GeV 0 distribution after event selection

  11. 0 event cut • 0 () sometimes seems an “e-like” events. • energy ratio (E1>E2) E2 /(E1+E2) < 0.2 : 100% missed • opening angle (cos) cos > cos17o = 0.956

  12. Pe/(|p|) Pe/ |p|(GeV)

  13. Event Numbers

  14. events at Korea e • e • 0 dominates at low energy (Erec<1GeV) • CCQE event is larger than the others • Erec=0.4-2.8GeV •  • Almost CCQE • Resonant mode is comparable at low energy • Erec=0.4-5.0GeV  sin22RCT=0.1, MNS=0.0

  15. events at SK e • e • CCQE event is dominant • Erec=0.4-1.2GeV •  • Event from resonance is smaller. • Erec=0.4-5.0GeV  sin22RCT=0.1, MNS=0.0

  16. 2 • Best combination • mass hierarchy • CP phase (MNS) • Effect • 0, resonance mode

  17. input and systematic • Solar • sin22 = 0.83 0.07, m2 = (8.2  0.6) 10-5 eV2 • Atmospheric • sin22 = 1.000.96, m2 = 2.5 10-3 eV2 • matter density (uncertainty 6%) •  = 2.6 / 3.0 (g/cm3)(SK/Korea) • Systematic • flux normalization (3%) (each flavorto SK/Korea) • fiducial volume (3%) (SK / Korea) • CCQE  (3%) ( / ) • Resonance (10%) ( / ) • 0 (30%) ( = ) • efficiency (100-1%/905%) ( /e) • miss PID (11%) #total:26

  18. statistics systematic input expected error of reactor exp. 2 -rule of the game- Reactor experiments helps T2KK to solve the degeneracy.

  19. Condition • fiducial volume • SK : 22.5 kton Korea : 100 kton • exposure • 5 x 1021 POT • no anti-neutrino phase • base-line and off-axis • SK: L=295km with =2.5o or 3.0o • KR: L=1000-1200 km with =(0.5o ~ 3.0o) / 0.5o step • Previous results for mass hierarchy • 3.0@SK and 0.5@Kr (L=1000km) is the best combination 2 = 22, input : normal, sin22rct = 0.10, MNS=0.0 2 = 21, input : inverted, sin22rct = 0.10, MNS=0.0

  20. Results 2.5@SK 3.0@SK • Best combination is still SK(3.0) and Kr(0.5) L=1000 2=13 (input : normal) 2=11 (input : inverted) • contribution to 2 (normal) • Previous Setup 22.9 • matter density (SK) 0.5 • resonance 2.7 • density error -0.6 • miss ID (-e) -1.0 • reconstruction -2.3 • efficiency (e) -2.3 • 0 background -6.5 • total 13.4 normal normal positive 2.5@SK 3.0@SK negative inverted inverted sin22RCT=0.1, MNS=0.0

  21. 25 25 9 9 Contour (input : normal) MNS~ 30o sin22rct ~ 0.05 sin22rct ~ 0.09 MNS~ 45o

  22. summary The others, reconstruction, matter profile, and so on, do not change the results drastically. “3.0 at SK and 0.5 at 1000km” is still the best. 2 23  13 (input : normal) 21  11 (input : inverted) MNS 30o  45o(3 2)

  23. Thank you for your attention

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