Results in Neutrino Oscillations from Super-Kamiokande I

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NNN07 at Hamamatsu, Oct. 2-5, 2007
Report of the T2KK Workshop
Soo-Bong Kim, Seoul National University,
sbkim_at_phya.snu.ac.kr
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1st 2nd Workshops on T2KK
http//newton.kias.re.kr/hepph/J2K
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Summary of the 1st 2nd Workshops

• T2KK motivation
• - T2K-II with HK needs to resolve the
  degeneracy in the measured CP
• phase based on the longer L and the larger
  matter effects

• Location of the detector(s)
• - 2000 m.w.e. depth for most of physics
  (H.Sobel, T2KK05)
• - a candidate site at Kamioka (K.Nakamura,
  T2KK05)
• - mountains of 1,200 meters in height are
  found almost everywhere in
• the interesting region of Korea (D.Son,
  T2KK05, C.Ryu, T2KK06)

• Resolving the oscillation parameter degeneracy
• - mass hierarchy CP phase (H.Minakata,
  N.Okamura, E.J.Jeon, T2KK05
• 
  S.K.Kang, H.Minakata, K.Senda, T2KK06)
• - sensitivity as a function of off-axis angle
  at far detector (N.Okamura, T2KK05/06,
• F.Dufour, T2KK06, K.Okumura,
  T2KK06, A.Rubbia, T2KK05/06)
• - liquid Ar sensitivity (A.Rubbia, T2KK05/06)

• Probing non standard physics
• - NSI (P.Ko, H.Sugiyama, T2KK06)
• - test of unitarity (B.Gavela, T2KK06)

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3rd Workshop on T2KK
http//www-rccn.icrr.u-tokyo.ac.jp/workshop/T2KK07
/
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Site Study for Hyper-Kamiokande

• Site studies and cavern analyses by Mitsui
  Mining Smelting Co. Ltd. (K. Nakamura, T2KK05)

• Study on the joint rock mass by Shimizu
  Corporation (N. Wakabayashi, T2KK07)

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Site Study for the Korean Detector

• mountains of 1,200 meters in height are found
  almost everywhere in
• the interesting region of Korea ? Search
  for a candidate site
• (D.Son, T2KK05, C.Ryu, T2KK06/07)

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Oscillation Parameter Degeneracy

• Resolving the octant degeneracy
• (H. Minakata, T2KK05/06, S.K.Kang T2KK06/07)

If q23 ?p/4, is it gtp/4 or ltp/4 ?
q13
Sign of Dm232
ne nm nt
n3
ne nm nt
n3
n2
n1
or
n3
CP ?
How much can T2KK contribute to these
measurements?
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How to solve the octant degeneracy?
H. Minakata, T2KK06
Strategy Use information which are not
proportional to sin22?23 x sin22?13
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Sensitivity of Mass Hierarchy
C. Ishihara, T2KK07
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Resolving the degeneracy T2K-II vs. T2KK
T2K-II (Kamioka only)
T2KK (Kamioka Korea)
Octant of q23 not resolved
Mass hierarchy not determined
T2KK has a good sensitivity to resolve the
parameter degeneracies.
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Sensitivity to the Octant of ?23
S. Nakayama, T2KK06
sin22q230.96
OA 2.5 degree for both Kamioka and Korea
sin22q230.99
2s
3s
Octant ambiguity of q23 can be resolved at 2s if
sin22q23 lt 0.97 (almost independent of the value
of sin22q13 and mass hierarchy).
T2KK could resolve the 8 hold degeneracy of the
oscillation parameters.
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Sensitivity on Off-axis Angles of the Korea
Detector
N.Okamura, T2KK05/07
Suggested that the higher energy beam is better
due to the larger matter effect.
1.0 to 3.0 degree off-axis beam available in
Korea.

• However, background might be a serious issue for
  higher energy beam.
• Detailed Monte Carlo study (F.Dufour, T2KK06)
• Liquid Argon detector (A.Rubbia, T2KK05/06)

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Sensitivity on Baseline of the Korea Detector
K. Okumura, T2KK06
2.5 degree off-axis beam with L between 1,000km
and 1,250km is available.
Kamioka only
L1000km
L1050km
L1100km
L1150km
L1200km
L1250km
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Beam Energy Profiles at Sites in Korea
A. Rubbia, T2KK07
1.0 to 3.0 degree off-axis beam available in
Korea.
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Signal BG for Various Off-axis Beams
F.Dufour, T2KK06
Korea
Kamioka
1.5 degree
1.0 degree
2.5 degree
signal
signal
BG
BG
sin2(2q13)0.1 d1/2p 4 year neutrino run 4MW beam
2.5 degree
2.0 degree

• Smaller off-axis angle
• Larger matter effect at the 1st osc. Max..
• ? Low E BG more serious.
• (2nd osc. Max. difficult to see.)

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T2KK Sensitivities for Various OA Angles
F.Dufour, T2KK06/07
Mass hierarchy
CP violation
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Sensitivity of Mass Hierarchy
A. Rubbia, T2KK07

• The longer baseline higher rate improves mass
  hierarchy determination

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Liquid Ar Detector
A. Rubbia, T2KK05/06/07
Deep inelastic
Quasi-elastic

• Possibility to study exclusive final states also
  in Multi-GeV range
• Detector behaves as a very fine-grained
  tracking-calorimeter

Very small NC and other ne background even with
the multi-GeV beam. ? Good for near on-axis beam.
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Sensitivity of Liquid Ar Detector
A. Rubbia, T2KK05/06/07
OA 1.0 deg, 281021pot, 100 kton mass Very high
sensitivity, especially in the very small
sin22q13 region.
sin22q130.006
Mass Hierarchy
CP
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Probing Non-standard Neutrino Physics
P. Ko, T2KK06/07

• Quantum Decoherence

• Lorentz Symmetry/CPT Violation

• Flavor nonuniversal neutrino interactions with
  matter

See their upcoming paper.
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Summary

• T2KK is an interesting option to resolve the
  oscillation parameter degeneracy based on the
  longer baseline and an additional, identical
  detector in Korea.

• For the best experiment, T2KK needs further
  tuning of some of parameters such as baseline,
  off-axis angle, detector mass, etc.

• T2KK needs a study of more physics opportunities.