Download - Solar Fusion Prozesses
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H. Bethe
W. Fowler
Solar Fusion Prozesses
HomestakeKamiokande, SK
SNO
Gallex, Sage
Solare Spektrum und Experimente
Das Pionierexperiment: Homestake
Ray Davis, 1966
Neutrino Detektion
37Cl + e 37Ar + e
threshold energy 814 keV
target 615 t Perchlorethylen
exposition to solar neutrinos ~ 60 days
extraction of Ar - atoms
Detection of Ar decay
(T1/2 = 35 days)
Noble price 2002
The Homestake Experiment
Dakota (USA)
Empfindlich auf 7-Be und hauptsächlich auf 8-B Neutrinos
Resultat:
2.56 +_ 0.23 SNU
Sonnenmodell:
7.6 + 1.3 - 1.1 SNU
Beginn des „Solaren Neutrino Problems“ !
Ergebnis Homestake Chlor ExperimentErgebnis Homestake Chlor Experiment
SuperKamiokande
dimensions:
41.4 m (hight)
39.3 m (diameter)
water Cherenkov Detector (~ 50 kton high purity water)
solar- detection by neutrino – electron scattering
Energy threshold ~ 5 MeV (sensitiv to 8B - )
Auch SuperK detects only 45 % of expected events (this is only a bit more than
Homestake (Davis))
Ratenvariation übers Jahr Energie Spektrum
Keine Abweichung von der erwarteten Form des ß-Spektrums
Gallex & GNO
71Ga + e71Ge + e
Integral detection of solar all solar neutrinos !
~5 decays per extraction
Situation nach GALLEX Situation nach GALLEX (~ 20 Jahre nach Homestake)(~ 20 Jahre nach Homestake)
Theoretische Vorhersagen
Hinweis auf nicht standard Eigenschaften der Neutrinos
This was the first evidence for non standard neutrino properties(neutrino decay, oscillation..? )
Hypothesis: Neutrino Oscillation ((B. Pontecorvo)Condition
1) Eigenvalues of weak interaction #mass eigenvalues
2) Neutrinos are massive
ν(e) = ν(1)cos (θ) + ν(2) sin(θ) ν(μ) = ν(1)-sin (θ) + ν(2) cos(θ)
Time development
|νe(t) > = |ν1(0) > exp (-iE1 t ) + |ν2 (0) > exp (–i E2 t)with Ei ² = m1² + p1² und Δ² = m²2 – m²1
P ν(e) = 1- sin² 2θ sin² (1,27Δ²/E²(ν))
SNO: Sudbury Neutrino Observatory
geladene Stromwechselwirkung (cc)
e + D p + p + e
neutrale Stromwechselwirkung (nc)
x + D x + p + n
Elektronstreuung (cc + nc)
x + e x + e nc-events ~ 30 / d
es-events ~ 3 / d
cc-events ~ 30 / d (SSM)
Energie- spektrum
Räumliche Verteilung im Detektor
Richtungsverteilung
Insgesamt kommen genau so viele Neutrinos an wie vorausgesagt!
Sonnen-Sonnen- ändern ändern ihren ihren Flavour!Flavour! (sie verwandeln sich auf dem Weg zur Erde vom e-Typ in den oder -Typ)
Neutrino Flavour Transition prooved
nepe
Detektion von ReaktorneutrinosDetektion von Reaktorneutrinos
Ev > 1.8 MeVEv > 1.8 MeV
promptes event: Ev – 0.77 MeVSpektroskopie)
verzögertes event:MeV)2.2( dpn
180μsec180μsec
Phys. Rev. Lett. 90 (2003) 021802
1.5 x 1011
Gallium
Experiment at ILL
Gösgen
Bugey
Search for neutrino oszillations, solar neutrino astronomy at low energies
Solar neutrinos
Borexino
? ?
Oscillation of Neutrinos from the Atmosphere
Superkamiokande
2
1
cossin
sincos
e
21
22
221 mmm
E
Lm
P ee
2sin)2(sin1
)(22122
Survival probability:
0 1 2 3L in Losz
Neutrino Oscillations
L ≈ 20 km
L ≈ 13000 km
atmosphericneutrinos:Ev ~ GeV
E
LmP atm
atmx
222 27.1
sin2sin)(
Oscillations and Atmospheric NeutrinosPion production and
subsequent decays (incl. muon)
Atmospheric Neutrinos and SuperKamiokande
Charged current reactions
+ N + N` and
e + N e + N`
50 kt Water Cherenkov Detector
SuperKamiokande SuperKamiokande (Japan)(Japan)
ein Detektor mit ca. 50 kton ein Detektor mit ca. 50 kton ReinstwasserReinstwasser
atmosphärische und solare atmosphärische und solare Neutrinos Neutrinos
atm.: CC Wechselwirkungatm.: CC Wechselwirkung
Particle ID and the number of Cherenkov rings
e + N e + N’ + (X)
e + N e + N’ + (X)
Category 1: fully contained events, 1 ring
Here: Electron like event
+ N + N’ + (X)
Category 1: fully contained events, 1 ring
Here: Muon like event
+ N + N’ + + (X)
Fully contained events, multiple rings
Here: Muon event
Multi-ring event
Muon 480 MeV
Electron 0.7 GeV
Muon 1 GeV
Through going muon
zenith angle distributions null oscillation best fit with oscillation data
νμ
νe
Electron events Muon events
Up going Up going Neutrinos
e
No-oscillation
Oscillation
Result atmospheric Neutrino-Oscillations
Best fit:m2
atm = 2.5×10-3
eV2
sin22θatm = 1.0
Best fit:m2
atm = 2.5×10-3
eV2
sin22θatm = 1.0
Confirmed by
•MACRO (Gran Sasso)
•Soudan (USA)
•K2K accelerator long baseline (250 km) experiment
•MINOS (USA) acc. exp. in 2006
What do we know today about neutrino oscillation
• e solar neutrinos
non maximal mixing und
m2 ~ 10-4 eV2
• atmospheric neutrinos
• large mixing ( close to maximal)
m2~ 2.5 x 10-3 eV2
e
Parametrization of Neutrinomixing
Neutrino-mixing matrix: • 3 mixing angles: θ12, θ23, θ13
• 1 CP-violating Dirac-Phase: δ
Neutrino-mixing matrix: • 3 mixing angles: θ12, θ23, θ13
• 1 CP-violating Dirac-Phase: δ
In addition, if Majorana neutrinos:• 2 CP-violating Majorana-phasesIn addition, if Majorana neutrinos:• 2 CP-violating Majorana-phases
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
θsolθ13, δθatm