Precision measurement of mixing angles and CP
Hisakazu MinakataPUC-Rio
RENO50@KNRC-Seoul
PUC-Rio, where?
June 13, 2013
Maracana
June 13, 2013 RENO50@KNRC-Seoul
All the angles are measured !lepton CP phase d left
na=Uai ni
solar+KamLANDSK-atm+MINOS+T2K T2K-MINOS-DC-DB-RENO
June 13, 2013 RENO50@KNRC-Seoul
q12
RENO50@KNRC-Seoul
q12 has been measured by solar and KamLAND experiments
June 13, 2013
KamLAND Mar. 2013
RENO50@KNRC-Seoul
q12
• sin2q12 = 0.304 +/- 0.013
• Error of sin2q12 = 4.3%
• Error of Dm221 = 2.4%
June 13, 2013
KamLAND Mar.2013
June 13, 2013 RENO50@KNRC-Seoul
How to improve
q12?
RENO50@KNRC-Seoul
SADO idea/proposal (July 2004)
• “SADO” = Several tens of km Antineutrino DetectOr
• Basic idea: 1st oscillation minima of Pee is the right place for precision measurement of q12
June 13, 2013
HM-Nunokawa-Teves-Zukanovich Funchal, ArXiv 0407326 PRD(2005)
RENO50@KNRC-Seoul
Optimal distance estimated as 50-60 km
June 13, 2013
Without geo-nu 40km would be fine
RENO50@KNRC-Seoul
SADO-vs KamLAND sensitivity
June 13, 2013
SADO 3 s sensitivity ~ KamLAND 1 s sensitivity
June 13, 2013 RENO50@KNRC-Seoul
Solar+KamLAND and SADO are good competitors
• Tuned reactor may have better sensitivity with long-run because tuning L is powerful
2% (1s) in sin2q12 reachable with systematic error of 4%
Bahcall-Pena-Garay Slide at World Physics Summit
@Galapagos, June 22-25, 2006
Quark-Lepton Complementarity
June 13, 2013 RENO50@KNRC-Seoul
Bi-maximal mixing from neutrinos
Predicted value of q13 in this model agrees well with experiments ! Large q13 natural in QLC
HM-A.Smirnov PRD 2004
QLC is based on observation: q12 + qC = p/4
Impressive to see the real
proposals today!
June 13, 2013 RENO50@KNRC-Seoul
Sin2q12 error: RENO ~ 1% (K.K.Joo) Daya Bay II 0.63% claimed! (Yifang Wang), Talk both at ICRR)
Daya Bay II
June 13, 2013 RENO50@KNRC-Seoul
q13
RENO50@KNRC-Seoul
q13: RENO
• If added quadrature, sin22q13 = 0.1 +/- 0.018
• sin2q13 = 0.0257 +/- 0.0048
• Error of sin2q13 = 19%
June 13, 2013
RENO50@KNRC-Seoul
q13: Daya Bay
• If added quadrature, sin22q13 = 0.089 +/- 0.011
• sin2q13 = 0.0228 +/- 0.0029
• Error of sin2q13 = 13%
June 13, 2013
RENO50@KNRC-Seoul
How to improve q13?
• Continued running of reactor experiments• Can accelerator measurement supersade reactor
q13 accuracy? If yes, when?
• What is the ultimate error of q13 ?
• If sin22q13 = 0.1 +/- 0.005 5% error for sin2q13
• Is 2-3% error achievable for sin2q13 ? • Neutrino factory?• Reactor + identical 2 detector appears to be
practically the best way June 13, 2013
Memory of Lev Mikaelyan @ Kurchatov Inst.
RENO50@KNRC-Seoul
Ultimate error of q13?
June 13, 2013Daya Bay ultimate (syst. only)
P. Coloma etal. JHEP12
D(sin2q) / sin2 q = (1.6-2.0) (Dq / )q
June 13, 2013 RENO50@KNRC-Seoul
Least accuratel
y measured angle q23
RENO50@KNRC-Seoul
q23: mixing angle with the largest error of 10-20% level
June 13, 2013Concha etal. JHEP 2012
RENO50@KNRC-Seoul
Error of q23 is large because ..
• Jacobian effect:
• Octant degeneracy + exp. uncertainty merging of clone solution to true one
June 13, 2013
HM-Sonoyama-Sugiyama PRD 2004
June 13, 2013 RENO50@KNRC-Seoul
How to measure
q23 accurately
?
RENO50@KNRC-SeoulJune 13, 2013
Use solar term or R+A to solve q23 octant degeneracy
T2K-II + phase II reactorT2KKd=0 assumed
sin
2 2
q1
3
sin2 q23
sin
2 2
q1
3
> 3s2~3s
T2KK 2s(rough)
T2KK has better sensitivityat sin2 2q13 < 0.06~0.07 .
hep-ph/0601258
Hiraide etal. PRD2006
Kajita etal. PRD2007
RENO50@KNRC-Seoul
Use atmospheric neutrino to probe solar n oscillation
June 13, 2013
Hyper-K LOI : ArXiv 1109.3262
Barger etal. PRL 2012
June 13, 2013 RENO50@KNRC-Seoul
Toward measuring
d
RENO50@KNRC-Seoul
How to measure CP
• nm superbeam appears to be the prime candidate
• T2KK CP sensitivity ~ T2HK CP sensitivity
June 13, 2013
RENO50@KNRC-Seoul
Determination of d in correlation with q13?
• So far CP d measurement has been discussed in a framework of simultaneous d – q13 determination intrinsic d - q13 degeneracy enriched with unknown mass hierarchy
• Right framework? NO! Better setting: simultaneous d – q23 determination
June 13, 2013
People were focused on another cosmos ..
RENO50@KNRC-Seoul
Why q23 relevant for CP?
• In precision era for CP the errors of d will be dominated by uncertainty of s2
23
• D sind =• D cosd =
June 13, 2013
For a given set of (P, P-bar) with finite error, a change in s2
23 can be compensated by adjusting d
Error formula for CP d = h order unity
HM-Parke, ArXiv 1303.6178
June 13, 2013 RENO50@KNRC-Seoul
A new method for q23
and d
RENO50@KNRC-Seoul
Simultaneous q23– d determination
June 13, 2013
For a given set of (P, P-bar) there are 2x2=4 solutions of q23 and d
What you need is to switch q13 q23
everything goes through as in (q13-d) case
RENO50@KNRC-Seoul
1st Oscillation maximum
June 13, 2013
Things are much simpler in oscillation maximum
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1st Oscillation maximum (continued)
June 13, 2013
HM-Parke, ArXiv 1303.6178
RENO50@KNRC-Seoul
Use ne appearance channel
• simultaneous d – q23 determination by ne and ne-bar appearance channels
• q23 intrinsic degeneracyJune 13, 2013
RENO50@KNRC-Seoul
Breaking q23– d degeneracy
June 13, 2013
At 1st VOM
Spectrum information must solve the degeneracy!
Off 1st VOM
Hyper-K: DE= +/- 10%: LBNE: DE= +/- 20%:
RENO50@KNRC-Seoul
2nd vacuum oscillation maximum
June 13, 2013
At 2nd VOM, =3D p/2
DE= +/- 3%: Movement of clone solution is more prominent at 2nd VOM
RENO50@KNRC-Seoul
Conclusion
• Current status of mixing angle measurement outlined
• Some ideas seeking for better precision discussed
• Further improvement appear realistic for q12 (new projects) and q13 (continue running), but may not be for q23 at near maximal, because…
• Fortunately, if you measure d, then you automatically get q23!
June 13, 2013