Baryo-through-Leptogenesis

and CP violation in neutrino oscillations

José BernabéuU. de Valencia and IFIC

MODERN COSMOLOGY INFLATION, CMB and LSS

Centro de Ciencias deBenasque, August 2006

Baryo-through-Leptogenesis andCP violation in neutrino oscillations Baryogenesis

Origin of neutrino mass

Leptogenesis

Experiments 1998 2006

What is known, what is unknown

Second generation approved experiments for U(e3)

and third generation proposals for the CP phase δ

Interest of energy dependence in suppressed neutrino oscillations

Baryo-through-Leptogenesis andCP violation in neutrino oscillations

Electron Capture: how to reach a superallowed transition and a short lifetime for the radioactive ion.

Gamow-Teller resonance in the final state Definite neutrino energy. Rare-earth nuclei around 146Gd.

Electron Capture Facility for a monochromatic -beam

Electron neutrino flux in LAB frame

Physics reach for θ13 and δ

Feasibility and prospects

Baryogenesis

Particle Physics has a SM, except for neutrino physics. Cosmology has a SCM. But SCM + SM incompatible without new physical phenomena. BARYOGENESIS is probably one phenomenon demanding new physics.

The charge asymmetry of the Universe needs a dynamical generation, given by the Sakharov conditions: 1) B- Violation, “natural” in GUT’s and in SM (with sphalerons); 2) C and CP- Violation, experimentally established; 3) Deviation from thermal equilibrium <--> First order phase transition.

One number to be explained: (n(B)-n(Bbar))/n(photons)= 6 x 10*(-10).

In principle, Baryogenesis is possible within the SM, but… 1) The EW phase transition (Higgs) cannot be first order; 2) CP- Violation induced by the CKM mixing matrix among quarks is short by more than 10*10 in Asymmetry.

A possible scenario is Baryo-through-Leptogenesis NEW PHYSICS: NEW HEAVY MAJORANA PARTICLES, with L- violating interaction & mass terms, and NEW SOURCES OF CP-VIOLATION.

Origin of masses

Why are Neutrino Masses so small?

even for a smooth LOG – scale…

i) With νL only, massive neutrinos have to be Majorana

ii) A Majorana mass term can not be, however, generated by SSB in the SM. Take particle content of SM and ask: what is the lowest dimension non- renormalizable operator with SU(2) x U(1) gauge invariance?

Origin of masses

UNIQUEDim. 5

Origin of masses

FΛ

vM

2

1. L = 2

2. F mixing, LFV

3. After SSB of Leff:

Conclusion

Lmass for “light” neutrinos GENERATED from Leff (at present energies)

and from L = 2 interactions at high energies Λ

• Origin of ? 1. Heavy mass R ?: conventional “See-Saw”

2. Fierz-reordering: other models

Leff → Lmass

“see –saw”

type

Why so light?

Maj

Maj

Neutrino mass matrix

The Pontecorvo MNS Matrix

3

2

1

Ue

100

0

0

0

010

0

0

0

001

1212

1212

1313

1313

2323

2323 cs

sc

ces

esc

cs

scUi

i

For Flavour oscillations U: 3 mixings, 1 phase

Atmospheric KEK More LBL-beams

Appearance e!Reactor Matter in Atmospheric…

SolarKAMLAND

Even if theyare Majorana

After diagonalization of the neutrino mass matrix,

Experiments 1998 - 2006

Experiments 1998-2006 Solar neutrinos

Homestake: 1/3 deficit for intermediate energy neutrinos and CC detection

Kamiokande and SuperKamiokande: ½ deficit for high energy neutrinos and elastic scattering detection

Gallium experiments: 0.6 deficit for low energy neutrinos and CC detection

SNO solution: NC νx flux = 3 CC νe flux for high energy neutrinos + total flux compatible with astrophysical calculations

Solution in terms of neutrino oscillations in Sun matter for νe to an equal combination of νμ and ντ

KamLAND confirmation for reactor νe in terms of vacuum oscillations for long baseline detection

Experiments 1998-2006 Atmospheric neutrinos

Early deficit in the ratio N(νμ)/N(νe)

Zenith effect in SuperKamiokande: dependence for high

energy νμ neutrinos, non dependence for νe neutrinos + non

deficit for short baseline neutrinos + increasing deficit for baselines above 6000 Km

Soudan II and MACRO confirmed the results with some information on the L/E dependence

Solution in terms of neutrino oscillations for νμ to ντ

Confirmation from accelerator νμ K2K experiment:

survival probability + energy dependence

Neutrino flavour oscillations

2512

2

2323

2

108

104.2

eVm

eVm

What is known, what is unknown

81.02sin

00.12sin

122

232

o1013 ?

Majorana neutrinos ? 0: masses and phases

Absolute neutrino masses ? 3 H, Cosmology

Form of the mass spectrum Matter effect in neutrino propagation

First very recent results from MINOS

Energy resolutionin the detectorallows a bettersensitivity in Δm2

23 : compatible with previous resultswith some tendency to higher values

From Fermilab to Sudan, disappearance: L/E dependence

How many Δm2 ‘s ? All interpretations on neutrino oscillations in

terms of two Δm2 ‘s: atmospheric and solar, that is, three active neutrinos.

Los Alamos experiment would imply a new Δm2 of the order of (eV)2, i. e., at least one aditional sterile neutrino.

Near future results from MiniBoone should clarify the issue.

I will assume in the rest of the presentation three active neutrinos only.

Second generation approved experiments for U(e3) Appearance

experiments for the suppressed transition νμ νe : T2K, NOVA

Off-axis neutrino beamfrom Fermilab to Soudan From J-PARC to SK

Second generation approved experiments for U(e3) Disappearance experiment

from reactor νe: CHOOZ Double CHOOZ at short and intermediate baselines with near and far detectors.

The most stringent constraint on the third mixing angle comes from the CHOOZ reactor neutrino experiment with sin2(2θ13)<0.2. Double Chooz will explore the range of sin2(2θ13) from 0.2 to 0.03-0.02, within three years of data taking.

Interest of energy dependence in suppressed neutrino oscillations

)4

sin(4

)4

cos(~

)4

(sin2sin

)4

(sin2sin)(

ceInterferen

213

212

213

Solar

2122

1222

23

cAtmospheri

2132

1322

23

E

Lm

E

Lm

E

LmJ

E

Lmc

E

LmsP e

Appearance probability:

|Ue3| gives the strength of Pe→νμ

After atmospheric and solar discoveries and accelerator and reactor measurements → 13 , CP violation accessible in suppressed appearance experiments

δ acts as a phase shift

CONCLUSION

1. SM Baryogenesis seems inefficient.2. Leptogenesis has all the good ingredients. It needs a

Majorana fermion at high scales.3. Any link to present neutrino physics? SEE-SAW connects m(L) with M(R).4. Leptogenesis depends on CP-odd M(R).5. Neutrino masses and mixings determined by m(L) CP-Violating Neutrino Oscillations.6. How to observe CP-phase? Phase-shift in suppressed e-neutrino mu-neutrino transition.

Interest of energy dependence in suppressed neutrino oscillations

CP violation: )()( ee PP

CPT invariance + CP violation = T non-invariance

)()( ee PP No Absorptive part Hermitian Hamiltonian

CP odd = T odd = is an odd function of time = L !

)()( ee PP

In vacuum neutrino oscillations L/E dependence, so

This suggest the idea of a monochromatic neutrino beam to separate δ and |Ue3| by energy dependence!

Neutrinos from electron capture

Electron capture:

From the single energy e--capture neutrino spectrum,we can get a pure and monochromatic beam byaccelerating ec-unstable ions

2 body decay! a single discrete energy ifa single final nuclear level is populated

How can we obtain a monochromatic neutrino beam?

Forward directionZ protonsN neutrons

Z-1 protonsN+1 neutrons

boost

An idea whose time has arrived !

-In heavy nuclei (rate proportional to square wave function at the origin) and proton rich nuclei (to restore the same orbital angular momentum for protons and neutrons ) - Superallowed Gamow-Teller transition

The “breakthrough” came thanks to the recent discovery of isotopes with half-lives of a few minutes or less, which decay mainly through electron capture to a single Gamow-Teller resonance.

Ion Candidates

Ions must have a mean life short enough to allowthem to decay in the storage ring before they loseits electron.

The recent discovery of nuclei that decay fast enoughthrough electron capture opens a window for realexperiments.

Implementation

Brief recall :

Ions produced at EURISOL

Accelerated by the SPS

Stored in a storage ring, straight sections point to detector

The facility would require a different approach to acceleration and storageof the ion beam compared to the standard beta-beam, as the atomic electrons of the ions cannot be fully stripped.

Partly charged ions have a short vacuum life-time. The isotopes we willdiscuss have to have a half-life ≤ vacuum half-life ~ few minutes.

For the rest, setup similarto that of a beta-beam.

Electron neutrino flux Assuming no oscillation: - In the proper frame of the radiocative ion - In terms of LAB variables for energy EL and angle θL

where J is the Jacobian

- In the LAB, contrary to the proper frame, there is a correlation between EL and θL. For long baseline experiments, detected neutrinos are inside a narrow cone around θL = 0 , by adjusting

the long straight section of the decaying ring.

)(4

*2

EQEdEd

dEC

00

22 1

ddE

d

JddE

d

LL

)cos1( LJ

Electron neutrino flux- For γ >>1 the neutrino flux in the forward direction is given by

Flux:Branching ratio

- Notice the proportionality with γ2

We want to have a proper neutrino energy E0 low enough so that a given E=2γE0 , estimated from the baseline L, implies a high , and then higher neutrino flux.

Experimental Set-up

)(),;;()(18

),;( 1313 EEPENg

MEN

ee

CCA

d

),;( 13 EN

),( )0()0(13

-Number of muons produced in CC interactions in the detector at a fixed baseline L

Cross Section per water molecule

Statistical Analysis byCalculating

and fit to the value for the assumed parameters

by minimizing х2

),( )0()0(13

Experimental set-up

5 years 90 (close to minimum energy above threshold) 5 years = 195 (maximum achievable at present SPS)

Distance: 130 km(CERN-Frejus)

440 kton water ckov detector

Appearance &Disappearance

1018 decaying ions/year

OR … appropriate changes If higher production rates

Versus 10 years for each γ

Results for appearance and disappearance

Disentangling θ13 and δ

Much betterseparation for two different energies, evenwith lower statistics

Access to measure the CP phase as a phase-shift

The virtues of two energies

130 km

Fit of 13 , from statistical distribution

The principle of an energy dependent measurement is working and a window is open to the discovery of CP violation

Exclusion plot: sensitivity

Total running time: 10 years... Impressive!! Significant even at 1o

013

Exclusion plot: δ ≠0 sensitivity

Total running time: 10 years... Significant for θ13 > 40

Feasibility Acceleration and storage of partly charged ions

Experience at GSI and the calculations for the decay ring yield less than 5% of stripping losses per minute

A Dy atom with only one 1s electron left would still yield more than 40% of the yield of the neutral Dy atom

with an isotope having an EC half-life of 1 minute, a source rate of 1013 ions per second, a rate of 1018 ’s

per year along one of the straight sections could be achieved (M. Lindroos)

- A new effort is on its way to re-visit the rare-earth region on the nuclear cart and measure the EC properties of possible candidates. The best: a half life of less than 1 min with an EC decay feeding one single nuclear level.

Physics Prospects

Most important is to determine the full physics reach for oscillation physics with a monochromatic neutrino beam: it would allow to concentrate the intensity in the most sensitive points in E/L to disentangle δ… By increasing the boosted neutrino energy and varying the baseline: Canfranc?, Frejus?, a combination of the two L’s?… By combining EC neutrinos with - antineutrinos from 6He… How to improve cross section results for and e

for water?

Thanks to : C. Espinoza J. Burguet-Castell M. Lindroos

CONCLUSION 1. SM Baryogenesis seems inefficient.2. Leptogenesis has all the good ingredients. It needs a

Majorana fermion at high scales.3. Any link to present neutrino physics? SEE-SAW connects m(L) with M(R).4. Leptogenesis depends on CP-odd M(R).5. Neutrino masses and mixings determined by m(L) CP-Violating Neutrino Oscillations.6. How to observe CP-phase? Phase-shift in suppressed e-neutrino mu-neutrino transition.