Neutrinos

Louvain, February 2005Alan Martin

Arguably the most fascinating of the elementary particles.Certainly they take us beyond the Standard Model !

=E = mc2

SuperK, SNO(CC)

ChlorineGalliumSNO(NC)

SuperK, SNO(CC)

ChlorineGalliumSNO(NC)

Solar Neutrino Problem (circa 2000)

Experiment ReactionHomestake e+

37Cl 37Ar+eSAGE e+

71Ga 71Ge+eGallex + GNO e+

71Ga 71Ge+eKamiokande +Super-Kamiokande x+ex+e

GALLEX : Ga (e )SSM (e )

0.58 0.05

SAGE : Ga (e )

SSM (e )0.60 0.05

Homestake : Cl (e )

SSM (e )0.34 0.03

Super -K : SK (x )

SSM (e )0.451 0.015

0.017

eitherSolar models are incomplete/incorrect

orNeutrinos undergo flavor-changing

transformation

Sudbury Neutrino Observatory

1700 tonnes of inner shielding H2O

12.01m dia. acrylic vessel

17.8m dia. PMT Support Structure9456 20-cm dia. PMTs56% coverage

5300 tonnes of outer shielding H2O

Urylon liner

1006 tonnes D2O

Nucl. Inst. Meth. A449, 127 (2000)

2 km

to

su

rfac

e

Detecting at SNO

NCxx

npd

ES -- ee x x

CC-epd e p

• Low Statistics • (e) 6 () 6 ()

• Strong directionality:

• Measurement of e energy spectrum

• Weak directionality:

• Measure total 8B flux from the sun• e

1 0.340cos

e 18 (Te 10 MeV)

See : Phys.Rev.Lett. 89 (2002) 011301 Phys.Rev.Lett. 89 (2002) 011302

Solar Model predictions are verified: [in 106 cm-2 s-1]

Missing Solar ’s Found

e 1.76 0.05

0.05(stat.)0.09

0.09(syst.)106 cm 2s 1

3.410.45

0.45(stat.)0.48

0.45(syst.)106 cm 2s 1

8B shape constrained fit:

No 8B shape constraint:

CC ( e ) e

NC ( x ) e

ES ( x ) e 0.15

Null hypothesis of no flavour transformation rejected at 5.3

SSM (BP01) 5.05 1.01

0.81

SNOconstrained 5.09 0.44

0.43(stat.)

0.46

0.43(syst.)

SNOunconstrained 6.42 1.57

1.57(stat.)

0.55

0.58(syst.)

If CPT is conserved…(and LMA…)

Solar e

Predicts deficit in

Reactor e

~100 to 200 km

Complementary!

Why Kamioka?

P e sin2 2 sin2 1.27 m2

[eV2

] L[m]

E [MeV]

With L 175 km, E 5 MeV

Sensitive to m 2 2

5

175,000 1.27

4 10 5 eV2

51 reactors in Japan,80% of flux (or 68.5 GW of reactor power) from baseline of ~140 to 210 km

Is Oscillation Really the Solution?Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND)(Kamioka, Gifu Prefecture, Japan) reactor @ “right” baseline for directly testing the currently favoured LMA region

e p n e

e e 2

n p d (2.2 MeV)

2x coincidence

1 kt liquid scintillator as target

(inverse decay)

Reactor Anti-Neutrino FluxN

obs/N

no o

scill

atio

nNobserved – NBKG

Nno oscillation

= 0.611 ± 0.085 (stat) ± 0.041 (syst)

First observation of reactor anti-neutrino deficit

LMA prediction: m2 = 5.5x10-5 eV2

sin2 2 = 0.833

SuperK, SNO(CC)

ChlorineGalliumSNO(NC)

Electron neutrinos asexpected.

Evidence of mu-tauneutrino oscillations.

Should see evidenceof upgoing tau neutrinos

Atmosphericneutrinos

56 events seen---80 expected

0

4

2

8

10

6

-2

t

b

cs

d u

e

Log10m/eV

(m2atm)1/2

( m2sol)1/2

Upper limit on m

Neutrino masses are really special!

mt/(m2atm)1/2~1012

WMAP & LSS

KamLAND

Massless ’s?

• no R

• L conserved

Small masses?

• R very heavy

• L not conserved

/dm

dm

6p 4He + 2p +2e+ + 2

Twice

4p + e- 4He + e+ +2

Solar neutrino mixing

SuperK, SNO(CC)

ChlorineGalliumSNO(NC)