Cristina VOLPE(Institut de Physique Nucléaire Orsay, France)
Search for CP violationin the lepton sector
CP violation searches with future facilities
Conclusions
CP violation searches and astrophysics
OUTLINEOUTLINE
Introduction
Major advances in neutrino physics
e
SOURCEL
DETECTOR
e
AN IMPRESSIVE PROGRESS IN THE LAST DECADE in ourknowledge of its properties.
Pontecorvo, 1957
L/E ratio [km/GeV]
1 10 102 103 104
oscillationdecoherencedecay
1.61.41.2
10.80.60.40.2
data
/exp
ecta
tion
Many puzzles have been solved with an incredible impact on various domains of physics.
Among the fundamental implications…
The solar neutrino deficit problem is clarified.
We understand the energy production in stars.
Neutrinos are massive particles, contrary to whatwas believed for decades.
The origin of neutrino mass and its smallnessneeds to be understood.
It opens a new possibility to understand the matter versus anti-matter asymmetry in the Universe.
A key step for one of the major open questions in modern cosmology.
THE CP violating phase INTRODUCES A - ASYMMETRY.
3
e
1 12
23
13
3
2
1
1212
1212
1313
1313
2323
2323
100
0
0
0
010
0
0
0
001
cs
sc
ces
esc
cs
sci
ie 1
3
e
The two basis are related by a unitary matrix, called the Maki-Nakagawa-Sakata-Pontecorvo (MNSP) matrix.
ijijc cos ijijs sin
23 1312
THE 3-flavours OSCILLATION PARAMETERS In the case of three families, there are three mass eigenstates (1,2,3) and three flavour eigenstates (e,,).
23
21
22
23
21
22
3,1
2 mmmmmmmi
i Only two m2 are independent.
m212 m32
2
THE key OPEN QUESTIONS
> The mass hierarchy
> The third mixing angle 13
> The neutrino nature
> The Dirac phase
> The absolute mass scale
> The Majorana phases
Double-CHOOZ, Daya-Bay, T2K,..
KATRIN, MARE,…
Gerda, Cuore, Super-Nemo,…
from double-beta decay experiments
supernovae, -factories, double-beta,…
exciting discoveries might be close…
A wealth of experiments are under construction or at a R&D level.
13 – expected sensitivities
Discovery potential (90% CL) for sin2 213
from reactors and accelerators
P. Huber, M. Lindner, T. Schwetz, W. Winter, arXiv: 0907.1861
THE VALUE OF 13 CRUCIAL FOR FUTURE STRATEGIES.
CPV sensitivity
sensitivity limits (90% CL) from T2K, NOA and reactors
P. Huber, M. Lindner, T. Schwetz, W. Winter, arXiv: 0907.1861
LONG-TERM expensive PROJECTS might be necessary.
Long-term accelerator projects
> Super-beams - intense conventional beams from muon and pion decay > Beta-beams – intense and pure neutrino beams from boosted accelerated ions
> Neutrino factories – intense neutrino beams from stored muons
THE GOAL : to investigate very small 13 values, the Dirac CP phase and the mass hierarchy.
The beta -beam concept
ions at rest
ions are boosted
6He
6He
neutrino beams
Average neutrino energy : E = 2QFlux emittance : 1/.
No beam associated background (the -beams are produced from primary particles).
Zucchelli, PLB 2002
e6Li 6Li e
Beta-beams = 100
Low-energy = 5 -14
C. Volpe, Journ. Phys. G. 30 (2004), hep-ph/0303222.
Several beta-beam scenarios proposed
P. Zucchelli, Phys. Lett. B 2002
High-energy = 300
J. Burguet-Castell, D. Casper, JJ Gomez-Cadenas, P. Hernandez, F. Sanchez, Nucl. Phys. B695, 217 (2004), hep-ph/0312068.
and very high-energy = 1000
J. Bernabeu, J. Burguet-Castell, C. Espinoza, M. Lindroos, JHEP 0512 (2005) 014, hep-ph/0505054.
Electron-capture
See Volpe, Topical Review on “Beta-beams”, J.Phys.G34, R1 (2007) hep-ph/0605033
CP
THE standard baseline scenario
sourc
e
decayring
6He ,18Ne
PS
SPS
Proton driverSPL
ISOL productionISOL target &ion sourcebeam preparationECR pulsed
Ion accelerationLinac, 0.4 GeV
acceleration atmedium energyRCS, 1.5 GeV Acceleration to final energy
PS and SPS
e
To a far detector
IT REQUIRES THE PRODUCTION AND ACCELERATIONOF VERY INTENSE RADIOACTIVE IONS BEAMS (RIB).
8.7 GeV
93 GeVLss = 2.5 km
EURISOL
EURISOL Design Study (FP6 2005-2009) -> Conceptual Report
P. Zucchelli, Phys. Lett. B (2002)B. Autin et al. , J. Phys. G 29 (2003) 1785.
130 km
CERN
FREJUS
e
Frejus Underground Laboratory
60 m
MEGATONDETECTOR
65 m
MULTIPURPOSE DETECTORCP violation, (relic) supernova neutrinos and proton decay.
MULTIPURPOSE DETECTORCP violation, (relic) supernova neutrinos and proton decay.
THE SEARCH for CP and T violation:
CP T
(with Beta-beams) (conventional beams)
e (+) e (+)
e (-) e (-)Three technologies under study(water Cherenkov, scintillator,liquid argon) LAGUNA Design Study (2008-10)
Three technologies under study(water Cherenkov, scintillator,liquid argon) LAGUNA Design Study (2008-10)
THE standard baseline scenario
Two kinds of studies of the physics reach can be found :
1) based on values of the ion intensities and boosts that are obtained extrapolating well-known technologies and existing accelerators.
2)based on values of the ion intensities and boosts that are treated as “free” parameters, with the aim of exploring the conditions to achieve optimal sensitivities.
IN THE LITERATURE…
Sensitivity to 13 and CP violation
Mezzetto 2005
Campagne, Maltoni, Mezzetto, Schwetz, JHEP 0704:003 (2007). hep-ph/0603172
After 10 years running (5+5, or 2+8) with 440 kton detector,
5.8 (2.2) 10 18 6He (18Ne)/s, = 100
Synergy with athmospherics
Helps identify the mass hierarchy and the octant degeneracy.
Campagne, Maltoni, Mezzetto, Schwetz, JHEP 0704:003 (2007). hep-ph/0603172
First proposed in : . Hubert, Maltoni, Schwetz, Phys. Rev. D 71, 053006 (2005). hep-ph/0501037.
THE BETA-BEAM PROJECT IS A COMPETITIVE option.
Comparison with other facilities
ISSstudy
-beam
1
1
0.6
0.2
10-5 10-4 10-3 sin2213
Fract
ion
of
International Scoping Study Physics Working Group, arXiv: 0710.4947 .
close detector
PS
SPS
EURISOL
storage ring
BASELINE-nucleus cross sections(detector’s response,r-process, 2decay)
fundamental interactions studies (Weinberg angle, CVC test, )
PHYSICS POTENTIAL
astrophysical applications
PHYSICS STUDIED WITHIN THE EURISOL DS (FP6, 2005-2009)
EURISOL DS (2005-09): Some conclusionsTwo sets of candidate ions are being considered :6He/18Ne and 8B/8Li
The ion stacking method in the storage ring ok.
IMPORTANT PROGRESS ON THE FEASIBILITY PERFORMED.
Three ion production techniques have been and will be investigated.-the standard ISOL technique : the requires 6He intensity is achievable, the 18Ne intensity lower - direct production (M.Loislet-Leuven, M. Hass-Soreq, GANIL) : 6He and 18Ne intensities should be achievable- storage ring production : suitable for 8B/8Li.
The direct and storage ring production methods will be studied within EUROnu. C. Rubbia et al, NIM A 568(2006) 475.
Further work will be done within EUROnu both on the feasibility and on the physics reach.
If the ions are bunched to suppress the backgrounds, theremight be a conflict with the EURISOL requirements.
CP violation searches and astrophysics
Supernova neutrinos
E. Akhmedov, C.Lunardini & A.Smirnov, Nucl.Phys.B643 (2002) 339.
J Kneller and G.C. McLaughlin, arXiv:0904.3823.
A. B. Balantekin, J. Gava, C. Volpe, PLB662, 396 (2008), arXiv:0710.3112.
J. Gava, C. Volpe, Phys. Rev. D78, 083007(2008), arXiv:0807.3418.
Solar neutrinosH.Minakata and S. Watanabe, Phys. Lett. B 468, 256 (1999).
Walter Winter, Phys. Rev. D 74, 033015 (2006).
UHE neutrinos
NS
e
Core-collapse supernovae (SN)
99 % of the energy is emitted as neutrinos of all flavours in a short burst of about 10 s.
A possible site for thenucleosynthesis of the heavy elements, but present calculations fail to reproduce the observed abundances.
-PROPERTIES CAN HAVE EFFECTS IN THE STAR OR IMPACT THE SIGNAL IN A SN OBSERVATORY.
Neutrino propagation in media
There are also shock wave effects. These engender multiple resonances and phase effects.
Neutrino-neutrino interaction is important. A more complex problem : the neutrino evolution equations are non-linear.
IMPRESSIVE PROGRESS IN THE LAST FEW YEARS !
V() GF e.
e
e e
e
W
The Mikheev-Smirnov-Wolfenstein (MSW) effect (’78, ’86) : neutrino coupling with matter induces a resonant flavour conversion.
the beautiful explanation of the « solar neutrino deficit » problem !
E=20 MeV
t=1st=1.5s
Turbulence effects arejust being considered.
A lot of work still needs to be done …
A NEW UNDERSTANDING OF PROPAGATION IN SN :
See the review from Duan and Kneller, arXiv:0904.0974
Gava, Kneller, Volpe, McLaughlin, Phys. Rev. Lett. 103 (2009), arXiv:0902.0317
A SIGNATURE IN THE POSITRON TIME SIGNAL IF sin2213 > 10-5 OR sin213 < 10-5
The search for the third -mixing angle
FLUXES ON EARTHadiabatic
non-adiabatic
First calculation including the interaction and shock wave effects.
e + p n + e+
POSITRON TIME SIGNAL
The dip (bump) can be seen at 3.5 (1) sigma in Super-Kamiokande if a supernova at 10 kpc explodes..
29 MeV
15 MeV
The neutrino evolution equations in matter are
with
factorizes out easily and gives:
vacuum term
CP violation and core-collapse SNA. B. Balantekin, J. Gava, C. Volpe, PLB662, 396 (2008), arXiv:0710.3112
We have demonstrated under which conditions there can be CP violating effects in supernovae. Here the main steps :
matterterm
the T23 basis
The electron neutrino survival probability does not depend on .
This leads to the two following relations:
Evolution operator in the T23 basis
CP violation and core-collapse SN
J. Gava, C. Volpe, Phys. Rev. D78, 083007(2008), arXiv:0807.3418.
We have demonstrated that these relations also hold when the interaction is included.
Tree level
The electron neutrino flux in the SN:
AT TREE LEVEL THE e-FLUXES DO NOT DEPEND ON THE CP PHASE.
NS
The neutrinosphere is where neutrinos finally decouple from matter.
20 Km
L- neutrino fluxesat the neutrinosphere(Fermi-Dirac or power law )
THERE CAN BE CP-VIOLATION EFFECTS IN SUPERNOVAE.
In the Standard Model loop corrections for the v interaction with matter should be included.
Conditions for CP effects in SNBeyond the Standard Model mightintroduce differences in the and interaction wiht matter (Flavor Changing Neutral Currents, …).
at the neutrinosphere
The propagation Hamiltonian does not factorize any more !
AND also
More realistic case !
EFFECTS OF 5-10 % ON THE ELECTRON NEUTRINO FLUXES
in the SUPERNOVA.
- interaction and 1-loop
Standard MSW, tree level
Inverted hierarchy and small
Numerical results : effects on the flux ratios
J. Gava, C. Volpe, Phys. Rev. D78, 083007(2008), arXiv:0807.3418.
200 Km in the star
e (
= 1
80°)
/ e
( =
0°)
The electron fraction is a key parameter for the r-process nucleosynthesis :
VERY SMALL EFFECTS ON THE ELECTRON FRACTION.
Numerical results : effects on Ye
Ye (
= 1
80°)
/Ye (
= 0
°)
A. B. Balantekin, J. Gava, C. Volpe, PLB662, 396 (2008), arXiv:0710.3112
Conclusions
The value of 13 sets the strategy for CP violation searches.
Beta-beams - A very competitive option.-The report on the feasibility from the EURISOL DS soon available. Future studies (ex. ion intensity within EUROnu).
Neutrinos in core-collapse supernovae : We have set the basis for the exploration ofCP violation in dense media.
Andromeda (M31)
Danke.
Thank you!
Merci.
Grazie.