Neutrino Flavor ratio on Earth and at Astrophysical sources
K.-C. Lai, G.-L. Lin, and T. C. Liu,National Chiao Tung university
Taiwan
INTERNATIONAL SCHOOL OF NUCLEAR PHYSICS31st Course
Neutrinos in Cosmology, in Astro-, Particle- and Nuclear PhysicsErice-Sicily: 16 - 24 September 2009
Neutrino flavor ratio at sources
(0, 0, 1)
1
,,
000
0000
e
e
Source (1, 0, 0)
Muon damped source (0, 1, 0)
●
(1/3,2/3,0)Pion source
●
Basic measured parameter definition– R : The ratio of track to shower events.– S: The ratio of two flavor shower.
• Experimental results are limited by number of detected events, fluctuation R and S
• Assumed
e
e
SR
i
i
i
i
i
i
i
i
R
R
R
R
S
S
S
S
1
1
K. Blum, Y. Nir and E. Waxman, arXiv:0706.2070 [hep-ph].
Basic idea I:What is the real source we observed.
From measured data to original source:
P
True flavor ratio at sourceMeasured flavor ratio at Earth
Ri,th and Si,th
Ri,exp and Si,exp 2
1 region
2 < 2.3
2 < 11.8
3 region.
0
’0
’0
+
Choubey et al., PHYSICAL REVIEW D 77, 113006 (2008)
# 1: Only 10% R
• For E < 0.3PeV, difficult to distinguish e from . Only R
• Even at R/R ~ 10%, could not resolve muon damp source from pion source.
muon damp source
Pionsource
0
C.L.) (90% 019.0sin
,45.0sin
,32.0sin
132
09.006.023
2
02.002.012
2
R only is unable to determine the original source.
Measuring S is necessary.
M. C. Gonzalez-Garcia and M. Maltoni, Phys. Rep. 460, 1(2008); M. Maltoni, T. Schwetz, M. A. Tortola, and J. W. F.Valle, New J. Phys. 6, 122 (2004); S. Choubey, Phys. At.Nucl. 69, 1930 (2006); S. Goswami, Int. J. Mod. Phys. A21, 1901 (2006); A. Bandyopadhyay, S. Choubey, S.Goswami, S. T. Petcov, and D. P. Roy, Phys. Lett. B 608,115 (2005); G. L. Fogli et al., Prog. Part. Nucl. Phys. 57,742 (2006).
# 2-1: sin213 =0 for
• Can rule-out pion source from muon-damped source under R/R ~ 10%, S/S ~ (11~14)%
• Astrophysical hidden source (1/2, a, (2/3 –a)) can be rule-out too.
112/04/18 6
sin223 =0.45 sin223 =0.55
muon damp source
Pionsource
Astrophysical Hidden source
O. Mena, et al., PRD, 2007
# 2-2: sin213 = 0 for
• Can't rule-out muon-damped source from pion source under R/R ~ 10%, S/S ~ (11~12)%,
sin223 =0.45 sin223 =0.55
muon damp source
Pionsource
# 3-1: CP phase ,
Under R/R ~ 10%, S/S ~ 13%112/04/18 8
muon damp source
sin213 = 0 sin213 = 0.016 0.01(non zero)
Gray: =0Blue: =/2Red: =Pion
source
No dependence on CP phase
when (sin2 13) best-fit = 0
# 3-2: CP phase for
muon damp source
sin213 = 0 sin213 = 0.0160.01
Gray: =0Blue: =/2Red: =Pion
source
Under R/R ~ 10%, S/S ~ 13%
# 4-1: Critical uncertainty
R /R = 13%
S /S = 16%
• R /R = 5%
• S /S = 6%
Need several hundreds of neutrino events
to confirm the source.
Basic idea II: From Oscillation mechanism to new physics
flavor ratio measured on Earth
oscillation
Possible source flavor ratio
o
ij,
ij,
Decay
ij,
Other mechanism
Normal hierarchy:sin2θ13 < 0.14 and 0.37 < sin2θ23 <0.65Inverted hierarchy:sin2θ13 < 0.27 and 0.37 < sin2θ23 <0.69
Possible measured region with different strategy
Pion source with normal hierarchy
Muon source with normal hierarchy
Pion source with inverted hierarchy
Muon source with inverted hierarchy
*
* Inverted hierarchy is only possible
#
# Allow both hierarchySuper-Kamiokande Collaboration Phys. Rev. D 74, 032002 (2006)
All possible measured ratio for neutrino oscillation mechanism
1000 e
Neutrino oscillation#
# New physics
Beyond osciallationnormal hierarchy
inverted hierarchy
measured ratio
All possible source
One example: Decay with normal mixing angle
#
#
#: Only decay in this region is available.
Michele Maltoni et al JHEP07(2008)064
Another example: Decay with inverted hierarchy mixing angle
# ##
#: Only decay in this region is available.
Conclusion
• Part I• Measuring the R ratio only is not sufficient to
determine the source type.• The Critical uncertainties required to distinguish
between pion and muon damped source: for pion source: R /R = 5% S /S = 6% for muon source: R /R = 13% S /S = 16%
• Part II• New method to probe new physics.