1. Constraints for New Physics from Matter Effects on Neutrino Oscillation
Minako Honda (Ochanomizu Univ.)
and
Naotoshi Okamura (YITP)
Yee Kao (Virginia Tech.)
Alexey Pronin (Virginia Tech.)
Tatsu Takeuchi (Virginia Tech.)
based on
hep-ph/
hep-ph/
hep-ph/0611xxx
Joint Meeting of Pacific Region Particle Physics Communities Hawaii)

2. Today’s Theme
Do interactions between neutrinos and matter due to “New Physics” have an effect on neutrino oscillations?? p e- n
-beam e- n p
2. Can such effects be measured experimentally?? & be used to constrain “New Physics”??

3. Introduction

4. Universality Violation in NC
In many models beyond the SM, the universality of the couplings can be violated through radiative corrections.
Matter effect
beam
(a) charged current interaction
etc...
processes
ex) MSSM with
(b) neutral current interaction
lead to the NC universality violation

5. Direct exchange of New Particles W.Buchmuller et.al. PLB191,442(1987)
New Physics that can contribute to neutrino oscillations:
Supersymmetric R-parity violating couplings
Z’ in Gauged B-(Le+L+L)　with 
Z’ in Topcolor assisted Technicolor
Leptoquarks that couple different generations
etc.
E.Ma, PLB433,74(1988)
C.T,Hill, PLB345,483(1995) etc..
W.Buchmuller et.al. PLB191,442(1987)
e.g.)

6. Experimental constraints on universality violation in NC

7. The experimental constraints
~invisible decay width~
invisible
CERN
LEP/ OPAL, DELPHI, L3, ALEPH, SLD
NO CONSTRAINT
individual decay
No information is available on the individual decay widths into each flavor

8. The experimental constraints ~individual~
CHARM, CHARM CERN (’80s)
Z couplings to neutrinos
PLB180,303(1986), PLB320,203(1994)
cf ) Z couplings to charged leptons
LEP/ OPAL, DELPHI, L3, ALEPH, SLD
LEP invisible decay width
(total width is constrained.)

9. The theoretical possibility of universality violation in many models
The weakness of the current experimental bounds
PLB180,303(1986), PLB320,203(1994)
CHARM, CHARM II
It would be interesting to analyze the effect of such a violation on neutrino oscillations.

10. Plan of Talk Introduction Matter effect
effective potentials for neutrinos in matter
W and Z exchange
effective mixing angles and oscillation probabilities
When Neutral Current (NC) universality is violated
Can we see ? (A hypothetical experiment)
Fermilab NuMI beam ⇒ Hyper-Kamiokande detector (1Mt)
Constraints on "New Physics” (e.g. leptoquarks,…)
Summary

11. Matter Effect
effective potentials
effective Hamiltonian

12. The effective potentials (W & Z exchange)
charged current interaction
in ordinary matter
neutral current interaction

13. The effective Hamiltonian
U:MNS matrix CC NC
derived from universality violation in Neutral Current interaction
central value of CHARM
: measure of universality violation in NC
： effective mixing matrix
： effective mass-squares

14. Using the “Jacobi method”, …
mixing angles
oscillation probabilities
Using the “Jacobi method”, …

15. effective mixing angles (normal hierarchy)
: violation factor in NC
(details in our paper)

16. effective mixing angles (inverted hierarchy)
: violation factor in NC
(details in our paper)

17. Survival Probabilities ( )

18. The oscillation probabilities ( L=9,120km )
normal hierarchy
inverted hierarchy
atm</4
@17GeV
@17GeV
40%
40%
oscillation dip
neutrino beam energy [ GeV ]
neutrino beam energy [ GeV ]

19. The oscillation probabilities ( L=9,120km )
normal hierarchy
inverted hierarchy
neutrino beam energy [ GeV ]
neutrino beam energy [ GeV ]

20. The oscillation probabilities ( L=9,120km )
normal hierarchy
inverted hierarchy
atm</4
@17GeV
@17GeV
40%
40%
oscillation dip
neutrino beam energy [ GeV ]
neutrino beam energy [ GeV ]

21. Can be measured experimentally ? one example “Fermilab– HyperK”

22. to Japan from Japan(J-PARC)
small value ()
large matter effect
high energy
(E~O(10)GeV)
very long base-line
(L~O(10,000)km)
to Japan
from Japan(J-PARC)
Fermilab-Japan

23. Fermilab (NuMI) Hyper-Kamiokande [ L~9,120 km ]
HK (1Mt)
9,120km
~732x12
17GeV
NuMI Beam
no oscillation
Main Fermilab
MINOS @Soudan
We can expect a non-negligible event rate
732km
Fermilab

24. The expected number of events @ HK
after 5 years of data taking (1Mton)
4000
3500
3000
2500
number of events
2000
17GeV
1500
oscillation dip
1000
We can expect the green line to be clearly distinguishable from the blue or pink lines.
600
500 5 10 15 20 25 30
neutrino beam energy [ GeV ]

25. The constrains on universality violation 
2 / 14dof (8GeV-22GeV)
100
much tighter constraints than that from CHARM and CHARMII
10years 80
5years
3years 60
1year 40
99%C.L.
95%C.L. 20
90%C.L.
-0.025
0.025
-0.03
-0.02
-0.01
0.01
0.02
0.03
~0.005
~0.015

26. Constraints on “New Physics”
Leptoquarks
Z’ Gauged B-(Le+L+L) with 

27. W.Buchmuller et.al. PLB191,442(1987) Lower bounds on Leptoquark masses
1. Leptoquarks
S : scalar, V : vector,
subscripts : dim of SU(2) rep.
W.Buchmuller et.al. PLB191,442(1987)
Lower bounds on Leptoquark masses
dependence
0.65

28. 2. Z’ Gauged B-(Le+L+L) with  dependence on Z’ mass
E.Ma, PLB433,74(1988), etc..
dependence on Z’ mass
Lower bounds on Z’ mass
-0.005
0.005
5.5TeV

29. Lower limit on LHC LHC Gauged B-(Le+L+L), with 
LEP/HERA
Fermilab-to-HyperK
LHC
Gauged B-(Le+L+L), with 
LEP and SLD
Fermilab-to-HyerK
LHC
Fermilab to hyper-kamiokande experiment,
can lead to a “marked improvement”,
are comparable to the LHC result, and can be used as a “complimentary test”.

30. oscillation probability Fermilab Hyperkamiokande experiment
Summary
We investigated the matter effect on neutrino oscillation from universality violation in neutral current interactions.
The violation effects
normal
inverted
mixing angle
oscillation probability
L=9,120 km
17GeV
This result is highly sensitive to the value of sin2(223)
Fermilab Hyperkamiokande experiment
If sin2(223) is as small as 0.92, the current 90% lower bound,
a 5-year measurement of survival spectrum could place a model independent constraint on NC universality violation at the 1% level.

31. Fermilab HyperKamiokande experiment
A constraint on , can potentially place a strong constraint on possible “New Physics”.
Leptoquarks
Z’; Gauged B-(Le+L+L) with , etc…
Fermilab HyperKamiokande experiment
The indirect probe of these “new particles”
can improve the existing bounds
compete with the direct
If these particles is
can serve as an “independent” and “complimentary” test of the LHC result.

32. Back Up Slides

33. The effective potentials
charged current interaction
neutral current interaction
Fierz tran. 2 2
■ニュートリノの前方散乱振幅の実数成分を，物質がニュートリノに作用するポテンシャルエネルギーVと考える．
: electron number density
: neutron number density

34. The energy dependence of the effective mass squared differences
normal hierarchy
neutrino beam energy [ GeV ]
[eV2]
inverted hierarchy
neutrino beam energy [ GeV ]
[eV2]

35. The energy dependence of the effective mixing angles (neutrino)
normal hierarchy
neutrino beam energy [ GeV ]
[degree]
inverted hierarchy
neutrino beam energy [ GeV ]
[degree]

36. shift of effective mixing by 
Sum up the calculation,
: violation factor in NC
neutrino
anti-neutrino
normal
hierarchy
is shifted by
inverted
(details in our paper)
In the region of

37. average matter density
Matter Profile
depth (FNALHK)
density (FNALHK) +
average matter density

38. leptoquark many leptoquarks today, only S2 and V3,
the others are in our paper

39. Z’ boson gauged B-(Le+L+L ) with (++ = 3)
also, Topcolor Assisted Technicolor has Z’

40. SUSY ijk are already constrained »O(10-2),
R-parity violation
ijk are already constrained »O(10-2),
from lepton decays at tree level.