Neutrino Oscillations and Astroparticle Physics (1) John Carr Centre de Physique des Particules de Marseille (IN2P3/CNRS)

Pisa, 6 May 2002

Introduction to Astroparticle Physics Neutrinos - Number - Dirac and Majorana Neutrinos - Mass Measurements - Double Beta Decay - Mixing

Neutrino Oscillations

Cosmology

Dark Matter

High Energy Astronomy

What is Astroparticle physics ?

Particle Physics

Astronomy

Astrophysics and cosmology

PARTICLE

ASTROPHYSICS

Particle Astrophysics/Nuclear Astrophysics

Use input from Particle Physics to explain universe: Big Bang, Dark Matter, ….

Use techniques from Particle Physics to advance Astronomy

Use particles from outer space to advance particle physics

Story of the Universe

Make-up of Universe

Dark MatterEvidence : Need to hold together Galaxy Clusters Explain Galaxy Rotation velocities

Astronomy object candidates : Brown Dwarfs (stars mass <0.1 Msun no fusion) - some but not enough White Dwarfs ( final states of small stars) - some but not enough Neutron Stars/Black Holes ( final states of big stars.) - expected to be rarer than white dwarfs Gas clouds - 75% visible matter in the universe, but observable

Particle Physics candidates: Neutrinos - Evidence for mass from oscillation, not enough for all Axions - Difficult to detect …. Neutralinos - Particle Physicist Favourite !

charged particles protons ions electronsneutral particles photons neutrinos

at ground level :~ 1/sec/m²

Primary cosmic raysproduce showers in high atmosphere

Primary: p 80 %, 9 %, n 8 % e 2 %, heavy nuclei 1 % 0.1 %, 0.1 % ?

Secondary at ground level: 68 % 30 % p, n, ... 2 %100 years after discovery by Hess origin still uncertain

Cosmic Rays

Particle Acceleration

R 1015km, B 1010T E 1000 TeV

R 10 km, B 10 T E 10 TeV

Large Hadron Collider

Tycho SuperNova Remnant

E BR

( NB. E Z Pb/Fe higher energy)

Energy of particules accelerated

Dia

met

er o

f co

llid

er

Cyclotron Berkeley 1937

Saturne, Saclay, 1964

Particle Physics Particle Astrophysics

LHC CERN, Geneva, 2005

Terrestrial Accelerators Cosmic Accelerators

Active Galactic Nuclei

Binary Systems

SuperNova Remnant

Ultra High Energy from Cosmic Rays

1 102 104 106 108 1010 1012 Energy GeV

1 102 104 106 108 1010 1012 Energy GeV

cro

ss-s

ecti

on (

mb

)

par

ticl

e fl

ux

/m2 /

st/s

ec/G

eV

From laboratory accelerators From cosmic accelerators

FNAL LHC FNAL LHC

Flux of cosmic ray particles arriving on Earth

Particle cross-sections measured in accelerator experiments

Ultra High Energy Particles arrive from space for free: make use of them

Colliders Colliders

Fixed target beamlines

absorption cut-off mean free path -rays: + 2.7k >1014eV 10 Mpc

proton: p + 2.7k 0 + X >5.1019eV 50 Mpc

nuclei: photo-disintegration >5.1019eV 50 Mpcneutrinos: + 1.95K Z+X >4.1022eV (40 Gpc)

magnetic deflection

(rad)= L(kpc) Z B(G)/E(EeV) Galaxy B=2G, Z=1, L=1kpc -> =12deg at 1019eV

Photons absorbed on dust and radiation

Protons deviated by magnetic fields

Neutrinos direct

Multi-Messanger Astronomy

Neutrino Mass in the Universe

Neutrino History

1931 - Predicted by Pauli

1934 - Fermi develops a theory of radioactive decays and invents name neutrino

1959 - Discovery of neutrino (e) is announced by Cowan and Reines

1962 - Experiments at Brookhaven and CERN discover the second neutrino:

1968 - First evidence that solar neutrino rate half expectation: "solar neutrino problem”

1978 - Tau particle is discovered at SLAC by Perl et al.: infer third neutrino

1985 - First reports of a non-zero neutrino mass (still not confirmed)

1987 - Kamiokande and IMB detect bursts of neutrinos from Supernova 1987A

1988 - Kamiokande reports only 60% of the expected number of atmospheric

1989 - Experiments at LEP determine three neutrinos from Z line width

1997 - Super-Kamiokande see clear deficits of atmospheric and solar e

1998 - The Super-Kamiokande announces evidence of non-zero neutrino mass

2000 - DONUT experiment claims first observation of tau neutrinos

First observation of Neutrino

Reines and Cowan 1959: Target made of 400 l water and cadmium chloride near reactor. The anti-neutrino coming from the nuclear reactor interacts with aproton of the target matter, giving a positron and a neutron. The positron annihilates with an electron of the surrounding material, giving two simultaneous photons and the neutron slows down until it iseventually captured by a cadmium nucleus, implying the emission of photons some 15 microseconds after those of the positron annihilation. All those photons are detected and the 15 microseconds identify theneutrino interaction.

Three Generations of Particles Mass(Mev/c2)

At present only limits of absolute masses of neutrinosOscillations give neutrino mass differences

s

ue

d

e

c

t

b

106

104

102

1

102

104

106

Discovery of (?)

DONUT experiment, FNAL

Discovery of (?)

4

eventsidentified

Number of Neutrino Families

Data

From Big Bang Nucleosynthesis

Number of Neutrino Families From Big Bang Nucleosynthesis

Fraction 4He

Fraction Li

Lifetime (s) Reference 918 ± 14 [Chr72] 903 ± 13 [Kos86] 891 ± 9 [Spi88] 876 ± 21 [Las88] 877 ± 10 [Pau89] 888 ± 3 [Mam93] 878 ± 30 [Kos89] 894 ± 5 [Byr90]888.4 ± 4.2 [Nes92]882.6 ± 2.7 [Mam89]887.0 ± 2.0 [PDG94]

Dependence on Neutron lifetime

Number of Neutrino FamiliesMeasurements from LEP of width of Z resonance

N = 2.994±0.012

Neutrino Mass MeasurementsDirect mass measurements - Time-of-flight measurements from distant objects - Kinematics of Weak Decays

Indirect searches ( effects which only exist if M( ) 0 )

- Neutrino Oscillations - Neutrinoless Double Beta Decay

even

ts

energy

XY

M()=0M()0

Dirac and Majorana Neutrinos

( See Akhmedov ‘ Neutrino physics ’ : hep-ph/0001264 )

For massive fermion, mass term in Lagrangian:

Mass term couples left and right-handed components:

Dirac Neutrino: left and right-handed fields completely independentMajorana Neutrino : left and right-handed fields charge conjugates

then:

so:

Majorana neutrino is its own anti-particle

: Majorana field is self charge-conjugate

Dirac and Majorana masses

General neutrino mass term in Lagrangian:

where:

Mass matrices : Dirac mD, Majorana mL, mR

n species of neutrino: n n complex matrices

Supernova 1987a in Large Magellenic Cloud L = 50 kpc (150 light years )

p e ne

e+ e e + e, ,

Neutrino Mass from Time-of-flight

M(e ) < 23 eV/c2

t = 0 unknownuse arrival time as function of energy

time (sec) time (sec)

energy (MeV)

eve

nts

Limits on M( )

Measured in decays at LEPe+e + n (n=3, 5, 6)

contours are limits when E = 0

Limits on M( )

In tau rest frame energy of hadronic system h:

E*h =

m2 + mh

2 m2

2 m

Total decays 2939 : 2 + 52 : 3 2+

3 : 3 2+ 0

only events with high mh

contribute to M( ) limitM( ) < 18.2 MeV/c2 (95% CL)

Limits on M( )

M( ) < 170 keV/c2 (95% CL)

Limits on M(e )

Detailed study of end-point of spectrum: many experiments

Limits on M(e )

Mainz spectrometer

Limits on M(e )

End-point spectra

Troitsk experiment Mainz experiment

Limits on M(e )

0

Double Beta DecayA(Z,N) A(Z+2, N2)+2e

(neutrino-less)

A(Z,N) A(Z+2, N2)+2e+2e

Only possible M() 0Majorana neutrino

2

Must be energetically allowedand single beta decay suppressed

Only a few possible double beta isotopes

Example: 100Mo in MOON detector

100Mo 100 Ru + 2 e (+ 2 e )

Both: Double beta decay:

Solar neutrino: 100Mo + e 100Mo 100 Tc + e 100 Ru + e

Mo(42,48) Ru(44, 46)

Physics beyond Standard Model in 0

Right-Handed Currents

Majoron production

Supersymmetry

NEMO 3 (100Mo)At Modane laboratory in Frejus tunnel

Heidelberg-Moscow (76Ge)At Gran Sasso laboratory

signal of 2 expected 0

Half-life T½2 = 1.55±0.17 1021 years T½

0 > 3.1 1025 years (90% CL)

Summary of Double Beta Decay Results

Limits on Majorana neutrino mass

Latest News

August 2001 limit:T½

0 > 3.1 1025 years (90% CL) M < 0.3 eV /c2

January 2002 evidence:T½

0 = (0.8-18.3) 1025 years (95%CL) 1.5 1025 years: best value M = 0.11-0.56 eV /c2 (95% CL) = 0.39 eV /c2: best value

- same data, not all same people…..

Summary of Particle Data Group 2001

M( e ) < 3 eV /c2

M( ) < 190 keV/c2

M( ) < 18.2 MeV/c2

Majorana mass M(e ) < 0.24 eV /c2

( dependent on Nuclear Matrix Element)

Number of light : 2.994 0.012

Possible Neutrino Mass Splitting

Zero of mass scale ?

M(e) < 3 eV ?

0

Neutrino MixingAnalogy with quarks

For massive particles: flavour eigenstates can be different from mass eigenstates

=

d

s

b

d

s

b

Vud Vus Vub

Vcd Vcs Vcb

Vtd Vts Vtb

leptons quarks

U : leptonic mixing matrixV : quark mixing matrix, ( CKM matrix ) Standard Model, U and V unitary 3 3 complex matrices: Uk

* Uk =

=

e

Ue1 Ue2 Ue3

U1 U2 U3

U1 U2 U3

1

2

3

W decaysleptons quarks

W q q W l l

W e 1 Ue1 2 e 2 Ue2 2

e 2 Ue3 2

1 U1 2 2 U2 2

3 U3 2

1 U1 2 2 U2 2

3 U3 2

W u d Vud 2 u s Vus 2

u b Vub 2

c d Vcd 2 c s Vcs 2

c b Vcb 2

( t X m(t) > m(W) )

Unitarity: Ue1 2 + Ue2 2 + Ue3 2 = 1

etc.

Vud 2 + Vus 2 + Vub 2 = 1

Numerical Values

0.97 0.22 0.003

0.22 1.0 0.04

0.006 0.04 1.0

Vud Vus Vub

Vcd Vcs Vcb

Vtd Vts Vtb

Ue1 Ue2 Ue3

U1 U2 U3

U1 U2 U3

?

Possibilities for Leptonic Mixing

Ue1 Ue2 Ue3

U1 U2 U3

U1 U2 U3

0.97 0.22 0.003

0.22 1.0 0.04

0.006 0.04 1.0

1 0 0

0 1 0

0 0 1

1/2 1/2 0

1/2 1/2 1/2

1/2 1/2 1/2

No mixing like quarks bi-maximal mixing

If Ue3 = 0 no CP violation ( like Vub = 0 for quarks)

CP Violation in Neutrino Sector

Ue1 Ue2 Ue3

U1 U2 U3

U1 U2 U3 If Ue3 = 0 no CP violation ( like Vub = 0 for quarks)

CP conservation:

Same parameterisation as quark sector: