solar & atmospheric. june 2005steve elliott, npss 20052 outline neutrinos from the sun the...

Solar & Atmospheric

June 2005 Steve Elliott, NPSS 2005 2

Outline

• Neutrinos from the SunThe neutrinosPast experimentsWhat we know and what we want to learn

• Atmospheric NeutrinosThe neutrinosPast experimentsWhat we know and what we want to learn

June 2005 Steve Elliott, NPSS 2005 3

Solar Model Assumptions

• Hydrostatic Equilibrium– radiative & particle pressures balance

gravity

• Energy Transport– photon diffusion in deep interior

• Energy Generation– nuclear fusion

• Isotopic/Elemental Abundances– changes occur only by nuclear reactions– initially agrees with current surface

observations

June 2005 Steve Elliott, NPSS 2005 4

The pp fusion reactions

p + e- + p 2H + e

2H + p 3He +

3He + p 4He + e+ +e

3He + 4He 7Be +

7Be + e- 7Li + +e

7Li + p +

3He + 3He 4He + 2p

99.75% 0.25%

85% ~15%

0.02%15.07%

~10-5%

7Be + p 8B +

8B 8Be* + e+ + e

p + p 2H + e+ + e

June 2005 Steve Elliott, NPSS 2005 5

The energy spectrum

June 2005 Steve Elliott, NPSS 2005 6

MSW at high energies, vacuum at low.

€

β =2 2GFne Eν

δm2

Ratio of oscillation length in matter to vacuum

June 2005 Steve Elliott, NPSS 2005 7

Matter and Vacuum

matter

vacuum

About 1 MeVFor the Sun

If β < cos212 ~0.4then the oscillation probability is given by the vacuum averaged result.

he

p-p

h/0

30

51

59

June 2005 Steve Elliott, NPSS 2005 8

The Cl Experiment

Ray Davis and his tank of cleaning fluid

June 2005 Steve Elliott, NPSS 2005 9

Cl Operations

• 615 tons of C2Cl4 , 814-keV threshold• Homestake Gold Mine• Bubble He gas through to extract Ar• Ar trapped in cold trap.• PC filled with Ar gas (7% methane)• 37Cl is 24% abundant.

€

37Cl ν e ,e( )37 Ar

June 2005 Steve Elliott, NPSS 2005 10

The Homestake Mine

June 2005 Steve Elliott, NPSS 2005 11

The Cl Apparatus

June 2005 Steve Elliott, NPSS 2005 12

Cl Results

2.56 ± 0.16 ± 0.16 SNU

Expect7.5 SNU

June 2005 Steve Elliott, NPSS 2005 13

SAGE and Gallex (GNO)

• 71Ga(e,e)71Ge

• 71Ge has 11.4 day half life.

• Expose Ga to neutrinos

• Extract Ge and count via its decay.

June 2005 Steve Elliott, NPSS 2005 14

SAGE Operations

1. Add carrier to Ga.2. After about 3-4 weeks, extract

Ge carrier and solar neutrino induced Ge.

3. Synthesize counter gas and fill proportional counter.

4. Count sample for about 6 months.

June 2005 Steve Elliott, NPSS 2005 15

Map to SAGE

June 2005 Steve Elliott, NPSS 2005 16

Baksan Valley, UG Laboratory

June 2005 Steve Elliott, NPSS 2005 17

Reactor Layout

10 reactorsEach can hold 8 tons of GaKept warm so Ga is liquid

June 2005 Steve Elliott, NPSS 2005 18

Results - Solar Rate

€

70.8−5.2, −3.2+5.3, +3.7 SNU

Expect128 SNU

Each run saw about 6 signalEvents.

June 2005 Steve Elliott, NPSS 2005 19

Gran Sasso

Italy:Not too far from Rome

June 2005 Steve Elliott, NPSS 2005 20

GNO Layout

June 2005 Steve Elliott, NPSS 2005 21

GALLEX Results

Expected128 SNU

June 2005 Steve Elliott, NPSS 2005 22

Kamiokande & SuperK

• Elastic scattering of e- in a large water detector

• Mostly sensitive to e because CC cross section is about 6x higher than NC

June 2005 Steve Elliott, NPSS 2005 23

SNO

• ES, CC, and NC

• CC: d(e, pp)e-

– Sensitive only to e

• NC: d(x, np)x

– Sensitive to all x

• NC/CC ratio

June 2005 Steve Elliott, NPSS 2005 24

SNO data

Radius of event vertex Angle with Sun

June 2005 Steve Elliott, NPSS 2005 25

Event Energy

June 2005 Steve Elliott, NPSS 2005 26

NC vs. CC response

June 2005 Steve Elliott, NPSS 2005 27

The hierarchy questionN

orm

al

Inve

rted

June 2005 Steve Elliott, NPSS 2005 28

The “Dark Side” of solar neutrinos

€

e (t)

ν μ+τ (t)

⎛

⎝ ⎜

⎞

⎠ ⎟=

cosθ sinθ

−sinθ cosθ

⎛

⎝ ⎜

⎞

⎠ ⎟ν 1(t)

ν 2 (t)

⎛

⎝ ⎜

⎞

⎠ ⎟

Two “flavors” are involved in solar neutrino oscillations. e and a linear combination of and .

€

P(ν e → ν e ) = 1− sin2 2θ sin2 1.27δm2

ER

⎛

⎝ ⎜

⎞

⎠ ⎟

June 2005 Steve Elliott, NPSS 2005 29

The “Dark Side” of solar neutrinos II

For </4, 1 is mostly e. But for ’ =/2 - /4, 1 is mostly +. Thus, although oscillations in a vacuum cannot distinguish between and ’, matter oscillations can.

€

P(ν e → ν e ) = 1− sin2 2θ sin2 1.27δm2

ER

⎛

⎝ ⎜

⎞

⎠ ⎟

€

sin2 2θm =sin2 2θ

sin2 2θ + (LL0

− cos2θ )2That is cos2 changes sign.

June 2005 Steve Elliott, NPSS 2005 30

Solar Neutrino Results

there is no dark side

Early fit to solar neutrino data. Note solution space for tan>1.

Ph

ys.L

ett.

B49

0 (2

000)

125

June 2005 Steve Elliott, NPSS 2005 31

The addition of KamLAND

June 2005 Steve Elliott, NPSS 2005 32

What’s left to do?• Is our model of neutrino mixing and

oscillation complete, or are there other mechanisms at work?– Without luminosity constraint, pp and 7Be

fluxes poorly known.– With constraint, 7Be is still poorly known.

• Is nuclear fusion the only source of the Sun’s energy and is it steady state?

• What is the correct hierarchial ordering of the neutrino masses?

June 2005 Steve Elliott, NPSS 2005 33

Non-Standard transformation possibilities

• Violation of equivalence principle

• Violation of Lorentz principle

• Non universal coupling

• Violation of Lorentz invariance due to CPT violating terms

• Non-standard neutrino interactions

June 2005 Steve Elliott, NPSS 2005 34

Future Solar Neutrino Experiments

Experiment Target Reaction Threshold

Borexino ~300 t liq. Scint. ES ~250 keV

KamLAND ~600 t liq scint. ES ~250 keV

LENS 60 t In load in scint

CC

HERON 68 m3 LHe ES ~45 keV

CLEAN 40 t liq. Ne ES ~35 keV

MOON Few t of 100Mo CC 168 keV

June 2005 Steve Elliott, NPSS 2005 35

Atmospheric NeutrinosUp vs. Down

atmosphere

Detector

Primary

Cosmic Ray

~20 km

~10000 km

€

+ → + +

↓

→ e+ + ν e + ν μ

€

Expect Rμ / e =ν μ + ν μ

ν e + ν e≈ 2

Meas.Rμ / edata

Rμ / e MC

≈ 0.6 − 0.7

June 2005 Steve Elliott, NPSS 2005 36

IMB and Kamiokande• Previous large water Cherenkov detectors• Built to look for proton decay,

atmospheric neutrinos are a significant background: hence lots of study

• Kamiokande was able to lower threshold to see solar neutrinos

• Saw SN1987A, but not pdk• Statistically weak indication of

atmospheric neutrino oscillations• Led to plan for Very Large SuperK

June 2005 Steve Elliott, NPSS 2005 37

SuperK

• 1000 m underground

• 50,000 tons of water

• 12,000 pmts

June 2005 Steve Elliott, NPSS 2005 38

Results

June 2005 Steve Elliott, NPSS 2005 39

Maximal mixing and the future

If sin213 is different than 0, Earth matter effects can resonantly enhance the subdominate transitions depending on the sign of m23

2.

June 2005 Steve Elliott, NPSS 2005 40

Future Experiments

Experiment Target Status

SuperK 50 kt water Continue on

SNO 1 kt heavy water

Continue on

MINOS Iron magnetized calorimeter

Operating, but small

INO 30-50kt magnetized tracking calorimeter

proposal

UNO/HyperK Mt class water proposal

June 2005 Steve Elliott, NPSS 2005 41

SNO is “small” but deep

June 2005 Steve Elliott, NPSS 2005 42

Resources

• Andrew Hime colloquium

• APS neutrino study on solar and atmospheric neutrinos