Measuring CP violating phase from long baseline neutrino experiments Naotoshi Okamura (YITP, Kyoto Univ.) ICFP2005 Oct. 07, NCU

plan short review short review until now until now between CP phase and the others between CP phase and the others 8 fold ambiguity effect of matter delete, 3m : mixing, mass, matter how to delete Yet Another Problem, error one example summary

short review

parameters (3flavor) neutrino masses neutrino masses m 1 m 2 m 3 m 1 m 2 m 3 flavor mixing angles flavor mixing angles  12  23  13  12  23  13 CP phase CP phase  Majorana phases Majorana phases  1  2  1  2 neutrino physics 7/9 parameters neutrino oscillation squared-differences squared-differences  m 2 12  m 2 13  m 2 12  m 2 13 (  m 2 3 -m 2 1 ) flavor mixing angles flavor mixing angles  12  23  13  12  23  13 CP phase CP phase  Majorana phases Majorana phases nothing nothing 6 parameters

until today Solar Neutrino (SK, SNO, KamLAND(reactor)) Solar Neutrino (SK, SNO, KamLAND(reactor)) e ! e (anti- e ! anti- e ) e ! e (anti- e ! anti- e ) Atmospheric Neutrino (SK, K2K(LBL)) Atmospheric Neutrino (SK, K2K(LBL))  !  (anti-  ! anti-  )  !  (anti-  ! anti-  ) Reactor Neutrino (CHOOZ, PaloVarde) Reactor Neutrino (CHOOZ, PaloVarde) anti- e ! anti- e anti- e ! anti- e only survival probability & 2-flavor analysis even function of  and  m 2 Discard : LSND

notations mass squared difference independent parameters relation to experiments MNS matrix

categorize solar, matter effect helps full100%full100% (  12 <45) (>0) atmospheric, even function half50%half50% (  23 <>45) (<>0) unknown, will be measured non0%non0% (<0.16)(no)

3 ambiguity 3 ambiguity value of  23 (octant) 2 fold ambiguity unobserved parameters 2 fold ambiguity sign of  m fold ambiguity 2 fold ambiguity “best fit” is  23 =45 : no octant ambiguity

CP phase and the others

CP phase and mixing flavor changing case P(  ! e ) : realistic mode in near future. combination of mixing angles and CP phase U e3 : unknown, important to measure CP phase

CP phase vs. mixing angles L = 295 km, without matter effect combination of mixing angles and CP phase If we do not know the value of  13, we cannot determine the CP phase e.g.

CP phase and mass hierarchy   e combination of “sign of  13 ” and “cos  ” even odd

CP phase and matter Disturbed by the matter effect. Combination of mixing angles and CP phase. Mixing angles are changed by matter effect. If we do not know the matter profile correctly, we cannot estimate the CP phase, correctly.

CP phase and the others matter effect disturb

3m 3m mixing angles mass hierarchy matter effect

mixing angle mixing angle flavor conserving case insensitive : slightly depend on CP phase, via MNS elements. P( e ! e ) : independent of CP Reactor experiments are independent of CP phase KASKA, DayaBay, Double Chooz, and so on.

2m 2m mixing angles mass hierarchy matter effect

mass hierarchy 1 matter effect helps us A>>B

mass hierarchy 2 We can determine mass hierarchy independently, if matter effect is large. if matter effect is large. When L/E is fixed at oscillation maximum, L>1000 km : matter effect term dominate L<1000 km : CP phase term dominate

neutrino world CERN FNALJ-PARC J-PARC – SK ( 300km) and – Korea (1000km)

1m 1m mixing angles mass hierarchy matter effect

matter effect matter effect disturbs CP phase measurement. matter effect disturbs CP phase measurement. helps to determine the mass hierarchy. helps to determine the mass hierarchy. makes difference between and anti- makes difference between and anti- precisely” If we know the matter profile “precisely”, matter effect will not be a big problem. Cheer UP!! Geologist !!

0m 0m mixing angles mass hierarchy matter effect

CP phase and the others matter effect disturb Geologist reactor1000km

Japan && Korea » one example » way to CP phase hep-ph/ , with K.Hagiwara, K.i.Senda

Tokaimura-to-Kamioka (T2K) J-PARC ( J-PARC ( 50 GeV Proton Synchrotron POT/year Intensity of neutrino O(2) higher than K2K SK ( SK ( 50Kton water Cherenkov detector fiducial volume : 22.5Kton good e/  identification cannot measure the charge L=295 km

Neutrinos will go to Korea OAB : cone, umbrella L=295km,  =2.0  -3.0  L= km,  =1.0  -4.0  S-Korea Super-K J-PARC

today ’ s choice for hierarchy, angle and place. true : “normal” fit : “inverted” true : sin 2 2  13 = 0.1  free : fit  = 0.0  free

two distance is better than one SK onlyKorea only Combine SK only bad no matter Combine Better !! BAD Korea only not bad w/o reactor, difficult true : sin 2 2  13 = 0.06, CP : n £ 90 o fit : sin 2 2  13 = horizontal, CP : freely SO,SO GOOD

CP phase We can determine CP phase more, if Ue3 is measured. Ue3:freely normal hierarchy

summary CP Phase vs. 3m CP Phase vs. 3m mixing angles, mass hierarchy, matter effect mixing angles, mass hierarchy, matter effect mixing angle (Ue3:unkown) mixing angle (Ue3:unkown) reactor experiment reactor experiment mass hierarchy mass hierarchy 1000km is turning distance. 1000km is turning distance. matter effect matter effect not so bad guy. helps us. not so bad guy. helps us. Cheers UP!! Geologist !! Cheers UP!! Geologist !! Japan-Korea experiment Japan-Korea experiment  ! e and  ! 

Thank you for your attention