new views on the problem of cp violation
Post on 06-Feb-2016
44 Views
Preview:
DESCRIPTION
TRANSCRIPT
New Views on the New Views on the Problem of CP ViolationProblem of CP Violation
H. MinakataH. Minakata
Tokyo Metropolitan University Tokyo Metropolitan University (TMU)(TMU)
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Why do we look for leptonic CP violation?
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Lepton-quark correspondence
• Quantum anomaly tells us that leptons and quarks are related with each other in a deeper level => we want to know if leptonic KM phase is unsuppressed
“lepton-quark correspondence” in the spirit of Nagoya model (Sakata et al., ‘60th) Shoichi SakataShoichi Sakata
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Leptogenesis• Lepton # asymmetry g
enerated by Majorana converted to baryon # asym. by “spharelon”
• => standard model for baryogenesis?
• Need CP violating phases
• Related with leptonic KM phase
(Buchmuller et al.)(Buchmuller et al.)
(Fukugita-Yanagida ‘86)(Fukugita-Yanagida ‘86)
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Good old way
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Good-old way of measuring CPV
P(->e) = P
P(bar->ebar)
= CP[P]P = P - CP[P] = nonz
erogives you CP violation
A useful tool for --> representation: Bi-probability plot H.M. & H. Nunokawa (=MN), JHEP 10 (2001) 001
A useful tool for --> representation: Bi-probability plot H.M. & H. Nunokawa (=MN), JHEP 10 (2001) 001
N. Cabibbo …N. Cabibbo …
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
P = P - CP[P]; sign of m2 or CPV?P = P - CP[P] = P(->e; m2, , a) - P(bar->ebar; m2, , a)
= P(->e; m2, , a) - P(->e; - m2, -, a) If P is insensitive to =>
= P(->e; m2) - P(->e; -m2) = m2-odd P measures sign of m2 in -insensitive region P measures in matter-insensitive region
= P(->e; m2, -, -a)= P(->e; - m2, -, a) (if m2
solar /m2atm << 1)
= P(->e; m2, -, -a)= P(->e; - m2, -, a) (if m2
solar /m2atm << 1)
Low-E superbeam; MN, Sato, Richter, …
Low-E superbeam; MN, Sato, Richter, …
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
TV; Cleanest way of measuring CPV
P(->e)=P
P(e->)=T[P]
PT = P - T[P]
gives you T (=CP under CPT) violation
P = Acos + Bsin + CT[P] = Acos - Bsin + CPT = P - T[P] = 2 Bsin
If = 0 => PT = 0
Experimentally, it is NOT easy => beta beam!
Experimentally, it is NOT easy => beta beam! MN-Parke, hep-ph/0204171MN-Parke, hep-ph/0204171
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
New ways
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
New ways of measuring CPV?• Reactor-LBL combination• BNL strategy with several
oscillation maxima (neutrino only)
• Its low-energy version?
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Reactor measurement of 13
• Independent of , matter effect, 23, 12, solar m2
=> Pure measurement of 13
e disappearance probabilitye disappearance probability
(H.M. Sugiyama, Yasuda, Inoue, Suekane, hep-ph/0211111)
(H.M. Sugiyama, Yasuda, Inoue, Suekane, hep-ph/0211111)
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Reactor-LBL combination
• JPARC-HK neutrino mode, 2 years (4 MW & 540 kton, s/bg accounted)
• 50 ton detectors @Kashiwazaki-Kariwa NPP, 1-10 years
• CP violation can be detected by reactor-LBL combination ! (H.M. H.Sugiyama, hep-ph/0309323 v2 -> PLB)
Principle very simple ! => e appearance at OM + reactor 13 measurement gives you
Principle very simple ! => e appearance at OM + reactor 13 measurement gives you
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Detecting CPV by reactor-LBL combination; details
Realisticdb crucial in sensitivity estimate in phase II
Realisticdb crucial in sensitivity estimate in phase II
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Can Super-K Do the Job?
• JPARC-SK neutrino mode, 10 years (0.75 MW & 22.5 kton, s/bg accounted)
• 50 ton detectors @Kashiwazaki-Kariwa NPP, 1-10 years
• Though less sensitive, Though less sensitive, SK can do a job !SK can do a job !
In the case of “C-evaluation” by the HK review committee
In the case of “C-evaluation” by the HK review committee
the only way to detect CPV without HK?
the only way to detect CPV without HK?
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
We must know sign of m2 in advance, otherwise …
This is nothing but Parameter Degeneracy due to sign (m2)!
MN, JHEP 10 (2001) 001
This is nothing but Parameter Degeneracy due to sign (m2)!
MN, JHEP 10 (2001) 001
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Why so much ambiguity by sign-m2 degeneracy?
The reason is:• Large 2 - 1 (=
/2 ~ in overlapping region of different-sign m2 ==>
• CPC-CPV confusion
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
BNL strategy (hep-ex/0211001)
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
JPARC-HK vs. BNL proposal• L=295 km/E=0.7 GeV vs. L=2540 km/E=0.5-5GeV==> 1st oscillation maximum vs. 1st-3rd oscillation max. • Clean environment for CPV vs. exploring oscillation pattern, sign of m2
13, can prove solar m2, can run with only
<=background ?
<=background ?
1 1
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Low-energy version of BNL strategy?• JPARC accelerator com
plex funded => we will have low-energy neutrino superbeam
• Low-energy beam cannot see 2nd OM because of Fermi motion
• Depend onm2 L/2E => , 3 means the detectors placed at L and 3L =>
• 300 km: Kamioka• 900 km: Seoul, Korea!
Similar to 2-detector strategy in: MN hep-ph/9706281
Similar to 2-detector strategy in: MN hep-ph/9706281
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Shooting Korea
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Bi-probability plot for JPARC-Korea
• Korean detector more important for accurate determination of (steeper slope)
• It is hard to determine sign(m2) from neutrino run only
• Mathematically, there is no degeneracy apart from -> similar to
MN to appear =>
MN to appear =>
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
anti run at the oscillation maximum (reminder)
In the thinnest ellipse limit (KMN)
• There is no degeneracy apart from ->
• sin2is the “distance to the origin”
Kajita-MN, hep-ph/0112345Kajita-MN, hep-ph/0112345
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Conclusion• Real alternative to good-old -anti low-E super
beam does not appear to show up yet• Reactor-LBL may work but confidence level les
s than 2 even with Hyper-K
• BNL strategy interesting to explore but CP sensitivity less than 1 => very long-baseline setting loses statistics
(in conventional beams)• Need to determine sign m2, otherwise CPV-CP
C confusion
<= the only way to detect CPV without HK?
<= the only way to detect CPV without HK?
Low-E version exists but expensive
Low-E version exists but expensive
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
LBL measurement of 13
JPARC-SK 13 sensitivity; OA2°, 5 years
Very simple form!Very simple form!Very simple form !Very simple form !
Dec. 3-5, 2003 Neutrino Oscillation in Venice Hisakazu Minakata
Reactor-LBL complementarity I
• Pure measurement of 13 by reactors help resolve (2323) degeneracy• If lucky, one may see CP & mass hierarchy
(H.M. Sugiyama, Yasuda, Inoue, Suekane, hep-ph/0211111)
(H.M. Sugiyama, Yasuda, Inoue, Suekane, hep-ph/0211111)
top related