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Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino PhysicsCaren Hagner, Universität Hamburg
• What are neutrinos?• Neutrino mass and mixing• Neutrino oscillations• Oscillations of atmospheric neutrinos (SuperK)• Neutrino beams:Oscillation of accelerator neutrinos (OPERA)
• Solar neutrinos:Oscillation of solar neutrinos(Homestake, SNO, Borexino)
• KamLAND reactor neutrino experiment• Summary• Outlook: Majorana neutrinos
Astroparticle Physics:- Solar Neutrinos- Cosmic Radiation- Supernovae- Neutrino TelescopesApplications:
- Monitoring of Nuclear Reactors
- Geo physics- New Technologies
Cosmology:- early universe- structure formation- dark matter
Elementary Particle Physics:- Mass?- Matter – antimatter symmetry- Physics beyond the Standard Model
Neutrino Physics
Why are we doing Neutrino Physics?
Caren Hagner, Universität HamburgDESY Summer School 2010
Fundamental Particles
u
d
Quarks:Quarks:
e-
Leptons:Leptons:
vec
s μ-
vμt
b τ-
vτ
Photon GluonInteractions by exchange of bosons:Interactions by exchange of bosons: W,ZGraviton
Caren Hagner, Universität HamburgDESY Summer School 2010
Wolfgang Pauli postulates the Neutrino (1930)
Num
ber o
f E
lect
rons
Electron energy
One expected this
But this was observed!
eepn ν++→ −
Energy spectrum of electrons from β-decayEnergy spectrum of electrons from β-decay
neutrinopnelectron EcmcmE −−= 22
ν
Solution: The Neutrino
@CERN Geneva
1925 Kopenhagen
Wolfgang Pauli in Hamburg (1955)
1922 Assistant at Universität Hamburg1924 Habilitation in Hamburg (Discovery of the Exclusion Principle)1922 Assistant at Universität Hamburg1924 Habilitation in Hamburg (Discovery of the Exclusion Principle)
Caren Hagner, Universität HamburgDESY Summer School 2010
Q=-1/3
NeutronNeutron
d
ProtonProton
Transformation d-Quark → u-Quark:Electroweak Interaction!Transformation d-Quark → u-Quark:Electroweak Interaction!
Decay of the Neutron - Birth of a Neutrino Decay of the Neutron - Birth of a Neutrino
eepn ν++→ −
u
e-
veQ = +2/3
d
Q = -1/3
uQ = +2/3 eeud ν++→ −
Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino Properties
Neutral
Fermions with Spin ½
In the Standard Model: massless, stable, always left handed!
BUT: Today we know that neutrinos have mass0.05 meV < mv < 2 eVStandard Model must be extended!
pv
Spin
vL
Caren Hagner, Universität HamburgDESY Summer School 2010
How Neutrinos interactThe weak interaction
LLL bt
sc
du
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛
LLL
e
e ⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−−− τ
νμνν τμ
ev−e
+W−W
−e
ev
ev−μ
+W
μv−μ
+W
Caren Hagner, Universität HamburgDESY Summer School 2010
Charged Current
Exchange of a W Boson:
ev
−e
−Wd
u−W
μv −μ
−e evu
ud
d
np
+W
+μ
μv
ud
+π
Caren Hagner, Universität HamburgDESY Summer School 2010
0Zdd
μv μv
Neutral Current
Exchange of a Z0 Boson:
u
ud
d
nn
0Z
τv
−e −e
τv
Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino mass and mixing
Neutrino mixing!Neutrino mixing!
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛⋅⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛=
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
3
2
1
321
321
321
ννν
ννν
τττ
μμμ
τ
μ
UUUUUUUUU eeee
3 massive neutrinos: ν1, ν2, ν3 with masses: m1,m2,m3
Flavor-Eigenstates ve,vμ,vτ ≠ Mass-EigenstatesFlavor-Eigenstates ve,vμ,vτ ≠ Mass-Eigenstates
332211 vUvUvUv eeee ++=Example:
Caren Hagner, Universität HamburgDESY Summer School 2010
Parametrisation of Neutrino Mixing
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) Matrix: • 3 mixing angles: θ12, θ23, θ13• 1 Dirac-phase (CP violating): δ
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) Matrix: • 3 mixing angles: θ12, θ23, θ13• 1 Dirac-phase (CP violating): δ
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛−
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
−⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
−=
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛ −
3
2
1
1212
1212
1313
1313
2323
2323
10000
0010
0
00
001
ννν
ννν
δ
δ
τ
μ cssc
ces
esc
cssc
i
ie
Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino Mixing for 2 Flavors
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−
=⎟⎟⎠
⎞⎜⎜⎝
⎛
3
2
2323
2323
cossinsincos
νν
θθθθ
νν
τ
μ
323223 sincos vvv θθμ +=
Today we know that θ23≈45o:
( )3221 vvv +=μ
The probability that vμ has mass m2 is cos2θ23
e.g. probability that vμ has mass m2: 50%
mixing angle → probability to have a certain mass
( )3221 vvv +−=τ
Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino OscillationsNeutrino Oscillations
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−
=⎟⎟⎠
⎞⎜⎜⎝
⎛
3
2
2323
2323
cossinsincos
νν
θθθθ
νν
τ
μ
Flavor eigenstates vμ, vτ Mass eigenstates v2,v3with m2, m3
W
vμ
μ
source createsflavor-eigenstates
vτ
W
τ
p,n hadrons
detector seesflavor-eigenstates
v2
v3
propagation determined bymass-eigenstates
23,2
23,23,2 mpE +==ω
slightly different frequencies→ phase difference changes
Caren Hagner, Universität HamburgDESY Summer School 2010
2 Flavor Neutrino Oscillations2 Flavor Neutrino Oscillations
23
22
2 mmm −=Δ
⎟⎟⎠
⎞⎜⎜⎝
⎛⋅=→
oszLxP πθνν τμ
223
2 sin)2(sin)(
Oscillation probability
)eV (inGeV) (in48.2km) in( 22m
ELosz Δ⋅
=
Prob
abili
ty t
o fi
nd v
τ
Distance x in Losz
Losz, ∆m2 sin2(2θ)
Super-Kamiokande
atmospheric neutrinosaccelerator neutrinos
JAPANKamLAND
reactor neutrinos
JAPANCANADA
solar neutrinos
SNO
Important experimental results in recent years
ve→vμ,τ
OscillationΔm2 ≈ 8·10-5 eV2
vμ→vτ,(s)
OscillationΔm2 ≈ 2·10-3 eV2
Neutrino Oscillations were observed→ Neutrinos have mass!
+ NEW: BOREXINO @ LNGS (Italy)+ MINOS (USA)
Caren Hagner, Universität HamburgDESY Summer School 2010
Let us first look how muon neutrinos oscillate
Sources of muon neutrinos are:The atmosphere (comic rays) Neutrino beams at particle accelerators
These neutrinos have energies of a few GeV
Detection methods:Water Cherenkov, Plastic Scintillators,Drift Tubes, Fotographic emulsions
Primary cosmic ray
N
N
K
π
π
μ
ν
π
atmospheric neutrinos
Caren Hagner, Universität HamburgDESY Summer School 2010
Oscillation of atmospheric neutrinos (1998)
⎟⎟⎠
⎞⎜⎜⎝
⎛ Δ=→
]GeV[]km[]eV[27.1sin2sin)(
2222
νμ θνν
ELmP atm
atmx
L ≈ 20 km
L ≈ 13000 km
atmosphericneutrinos:
Ev in GeV range
Oscillation probabilityvaries with zenith angle θ θ
Super-Kamiokande
electron event
myon event
50kt H2O
12000 PMTs12000 PMTs
Super-Kamiokande
Caren Hagner, Universität HamburgDESY Summer School 2010
SuperK – atmospheric neutrinos
e–like events μ–like events
without oscillationoscillation (best fit)data
νe
e
νμ
μ
Full SK-I data set, 90% CL (PRD71 (2005) 112005):
sin22θ > 0.92 1.5·10-3 eV2 < Δm2 < 3.4·10-3 eV2
Caren Hagner, Universität HamburgDESY Summer School 2010
How to make Neutrino beams (Ev ≈ 1GeV-100GeV)
ProtonBeam
Target FocusingDevices
Decay Pipe
Beam Dump
νμπ,Kμ
few 100 GeV
few GeV
Beam composition (typical example):
• dominantly vμ
• contamination fromvμ (≈6%), ve (≈0.7%), ve (≈0.2%)
• vτ ≲ 10-6
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA
Neutrino beam (vμ) from CERN to Gran Sasso Underground Lab (Italy)Neutrino beam (vμ) from CERN to Gran Sasso Underground Lab (Italy)
732 km
? τμ vv →
LNGS
vτ Appearance! vτ Appearance!
Started in june 2008, running…
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA: CNGS beam
%4/ =μμ vv
%87.0/)( =+ μvvv ee
GeV17=vE
400GeV p on graphite target
4.5·1019pot/year
Caren Hagner, Universität HamburgDESY Summer School 2010
Querschnitt des NeutrinostrahlsCNGS beam at 732km(FLUKA 2005)
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA: Detection of vτ
vτ
W
τ-
p,n hadrons
15% )(
48% )(
18%
18%
0
0
τ
τ
τ
τμ
ππππτ
ππτ
τ
μτ
vn
vn
vve
vv
e
+→
+→
++→
++→
+−−−
−−
−−
−−τ-decay:
Lead
Emulsions
ντ
τ−
1 mm
μ-
μv
τv
Hadrons
Typical topology of τ-decay:“Kink” within 1mm from vertex
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA Target: Lead/Emulsion Bricks
Lead/Emulsion Brick(total ≈ 200000)
10X0
8kg
Scanning
44 μm emulsion sheet
Field of view:2d image: 16 tomographic images
Vertex reconstruction & kinematical analysis
300μm
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA - DetectorSupermodule 1
Target Region:- Target Tracker (Scintillator)- Lead/Emulsion Bricks (100.000 per Supermodule)
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA - DetectorSupermodule 1
Magnet-Region:Iron &
RPC Planes
B B
Precision Tracker:6 Planes of Drifttubes
Target
v μ
X
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA – Brick Manipulating System
suction cup vehicle
Loading Station
Robot to insert/extract bricks
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA Sensitivity
exposure: 5 years @ 4.5 x1019 pot / year
0.716.410.56.6vτ in OPERA
BKGDΔm2=3.0x103eV2Δm2=2.4x10-3eV2Δm2=1.9x10-3eV2
OPERA: 6200 νμ CC+NC /year19 ντ CC/year (for Δm2=2•10-3 eV2)
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA Event (vμ CC)
Caren Hagner, Universität HamburgDESY Summer School 2010
May 2010: OPERA finds 1st vτ Event!
Caren Hagner, Universität HamburgDESY Summer School 2010
OPERA 1st vτ Event
Track 4: Kink after 1335µmdaughter track 8
"Observation of a first ντ candidate event in the OPERA experiment in the CNGS beam" (Phys. Lett. B 691 (2010), 138-145)."Observation of a first ντ candidate event in the OPERA experiment in the CNGS beam" (Phys. Lett. B 691 (2010), 138-145).
Caren Hagner, Universität HamburgDESY Summer School 2010
Now we look at electron neutrinos
Electron neutrino sources are:The Sun (neutrinos) Nuclear reactors (anti-neutrinos)
These neutrinos have energies of a few MeV
completely different detection techniques necessary!
Solar Neutrinos (Ev ≈ MeV)Solar Neutrinos (Ev ≈ MeV)
MeV7.2622He4 4 +++→ +eep ν
“Neutrino light” from the Sun (Super-Kamiokande)energy of the neutrinos in MeV
Solar Neutrinos: “pioneering experiment”
Raymond Davis Jr., Homestake Experiment
Nobelprize 2002Nobelprize 2002
Rexp = 0.34 × SSM
−+→+ ee ArCl 3737ν
Eν > 814 keV
Since≈1970
Creighton Mine (Nickel)Sudbury, CanadaCreighton Mine (Nickel)Sudbury, Canada
Depth 2070m
1000t D2O1000t D2O
9500 PMTs9500 PMTs
Caren Hagner, Universität HamburgDESY Summer School 2010
Neutrino detection in SNO
xx vnpdv ++→+
−++→+ eppdv e
−− +→+ evev ee
NC
CC
ES
γ
SNO Result (salt-phase)(PRL 92, 181301, 2004)
1/3 of solar ve arrive as ve on Earth2/3 of solar ve arrive as vμ or vτ .Measured total flux = Predicted flux
(Standard Solar Model)
Caren Hagner, Universität HamburgDESY Summer School 2010
Parametrisation of Neutrino Mixing
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) Matrix: • 3 mixing angles: θ12, θ23, θ13• 1 Dirac-phase (CP violating): δ
Pontecorvo-Maki-Nakagawa-Sakata (PMNS) Matrix: • 3 mixing angles: θ12, θ23, θ13• 1 Dirac-phase (CP violating): δ
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛−
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
−⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛
−=
⎟⎟⎟
⎠
⎞
⎜⎜⎜
⎝
⎛ −
3
2
1
1212
1212
1313
1313
2323
2323
10000
0010
0
00
001
ννν
ννν
δ
δ
τ
μ cssc
ces
esc
cssc
i
ie
θsolθ13, δθatm
Θ23: 34o - 58o θ13<13o, δ ? θ12: 29o - 39o
Caren Hagner, Universität HamburgDESY Summer School 2010
What do we know about neutrino masses?
∆m2solar ≈ 8·10-5eV2, ∆m2
atm ≈ 2·10-3eV2
v3
v1
v2
≳ 0.05 eV
normal hierarchy
Δmsolar
Δmatm
v1
v2
v3
inverted hierarchy
Δmatm
Δmsolar
v3v1 v2≲ 2 eV
quasi - degenerate
vevμvτ
Caren Hagner, Universität HamburgDESY Summer School 2010
Summary of Neutrino OscillationsNeutrino Oscillations have been observed withsolar, atmospheric, reactor and accelerator neutrinos.Neutrinos have mass!The absolute neutrino mass has not yet been measured, allowed range: 0.05 eV < mv < 2 eVNeutrino mixing exists and is very different from quark mixing. Why?Measurements of third mixing angle have been startedIs there CP-violation for neutrinos?Is the neutrino a Majorana particle?Search for neutrinoless Double-Beta Decay (Evidence?)
Caren Hagner, Universität HamburgDESY Summer School 2010
Many interesting results expected in next yearsMany questions still waiting to be solved by some of you!