Kosmologietag Bielefeld, 3 May 2011 Thomas Schwetz-Mangold · 2012. 5. 7. · News from neutrinos...

News from neutrinosKosmologietag Bielefeld, 3 May 2011

Thomas Schwetz-Mangold

Max-Planck-Institut für KernphysikHeidelberg

T. Schwetz 1

Outline

Introduction

3-flavour oscillationsRecent developements on θ13Comments on lepton mixing patternOpen questions

Sterile neutrinosThe reactor anomalyGlobal sterile neutrino fit

Conclusions

T. Schwetz 2

Introduction

Outline

Introduction



Conclusions

T. Schwetz 3

Introduction

Lepton mixing

if neutrinos have mass there can be a mis-match between neutrino andcharged-lepton mass basis

LCC = − g√2

W ρ∑

α=e,µ,τ

3∑i=1

νiLU∗αiγρ`αL + h.c.

LM = −12

3∑i=1

νTiL C−1νiLmν

i −∑

α=e,µ,τ

¯αR`αLm`

α + h.c.

⇒ Pontecorvo-Maki-Nakagawa-Sakata (PMNS) lepton mixing matrix: Uαi

T. Schwetz 4

Introduction

Neutrino oscillations

W

lα

W

lβ

νβνα

detectorneutrino source

"long" distance

neutrino oscillations

|να〉 = U∗αi |νi 〉 e−i(Ei t−pi x) |νβ〉 = U∗βi |νi 〉

oscillation probability: Pνα→νβ=

∑jk

UαjU∗βjU∗αkUβk exp

[−i

∆m2kjL

2 Eν

]

∆m2kj ≡ m2

k −m2j : oscillations are sensitive only to mass-squared differences

T. Schwetz 5

Introduction

2-neutrino oscillations

Two-flavour limit:

U =

(cos θ sin θ− sin θ cos θ

), P = sin2 2θ sin2 ∆m2L

4Eν

0.1 1 10 100L / Eν (arb. units)

0

0.2

0.4

0.6

0.8

1

Pαβ

4π / ∆m2

sin2 2θ

"short"distance

"long"distance

"very long"distance

T. Schwetz 6

Introduction

Neutrinos oscillate!

KamLAND (νe → νe)

(km/MeV)eν/E0L

0 10 20 30 40 50 60 70

Surv

ival

Pro

babi

lity

0

0.2

0.4

0.6

0.8

1

1.2

1.4 eνData - BG - Geo CHOOZ dataExpectation based on osci. parameters

determined by KamLAND

> 5σ evidence for spectral distortion

MINOS (νµ → νµ)

Psurvival ≈ 1− sin2 2θ sin2(

∆m2

4LEν

)I neutrinos have to have mass (non-degenerate)I mixing: interaction state is a superposition of different mass states

T. Schwetz 7

Introduction

Global data on neutrino oscillations

from various neutrino sources andvastly different energy and distance scales:

sun reactors atmosphere accelerators

Homestake,SAGE,GALLEX KamLAND, CHOOZ SuperKamiokande K2K, MINOS, T2KSuperK, SNO, Borexino

I global data fits nicely with the 3 neutrinos from the SM

I a few “anomalies” at 2-3 σ: LSND, MiniBooNE, reactor anomaly,no LMA MSW up-turn of solar neutrino spectrum

T. Schwetz 8

3-flavour oscillations

Outline

Introduction



Conclusions

T. Schwetz 9


3-flavour oscillation parameters

νeνµ

ντ

=

Ue1 Ue2 Ue3Uµ1 Uµ2 Uµ3Uτ1 Uτ2 Uτ3

ν1ν2ν3

∆m231 ∆m2

31 ∆m221

U =

1 0 00 c23 s230 −s23 c23

c13 0 e−iδs130 1 0

−e iδs13 0 c13

c12 s12 0−s12 c12 0

0 0 1

atmos+LBL(dis) Chooz+LBL(app) solar+KamLAND

3-flavour effects are suppressed: ∆m221 ∆m2

31 and θ13 1 (Ue3 = s13e−iδ)

⇒ dominant oscillations are well described by effective two-flavour oscillations⇒ CP-violation is suppressed by θ13 and ∆m2

21/∆m231

T. Schwetz 10


3-flavour oscillation parameters

νeνµ

ντ

=

Ue1 Ue2 Ue3Uµ1 Uµ2 Uµ3Uτ1 Uτ2 Uτ3

ν1ν2ν3

∆m2

31 ∆m231 ∆m2

21

U =

1 0 00 c23 s230 −s23 c23

c13 0 e−iδs130 1 0

−e iδs13 0 c13

c12 s12 0−s12 c12 0

0 0 1

atmos+LBL(dis) Chooz+LBL(app) solar+KamLAND

3-flavour effects are suppressed: ∆m221 ∆m2

31 and θ13 1 (Ue3 = s13e−iδ)

⇒ dominant oscillations are well described by effective two-flavour oscillations⇒ CP-violation is suppressed by θ13 and ∆m2

21/∆m231

T. Schwetz 10


The dominanting oscillation modes

I solar neutrinos Homestake, SAGE+GNO, Super-K, SNO, Borexinoνe → νµ,τ LMA-MSW with ∆m2 ∼ 7× 10−5eV2 (matter effect)

I Kamland reactor neutrino experiment (180 km, vacuum osc)νe disappearance with Eν/L ∼ 7× 10−5eV2

I atmospheric neutrinos Super-Kamiokandelong-baseline accelerator experiments K2K (250 km), MINOS (735 km)νµ disappearance with Eν/L ∼ 2× 10−3eV2

T. Schwetz 11


The dominanting oscillation modes

0.2 0.4 0.6 0.8

sin2θ12

0

5

10

15

∆m2 21

[ 10

-5eV

2 ]

solar neutrino exps.

KamLAND

combined

H

0 0.25 0.5 0.75 1

sin2θ23

1

2

3

4

∆m2 31

[ 10

-3 e

V2 ]

MINOS

atmospheric

global

sin2 θ12 ≈ 0.3 sin2 θ23 ≈ 0.5

∆m221

∆m231≈ 1

30

T. Schwetz 12


Neutrino mass spectra and mixingINVERTEDNORMAL

[mas

s]2

3ν

ν2

ν1

ν2ν1

ν3

νe

µν

ντ

∆m231 > 0 ∆m2

31 < 0

I ν1 is dominantly νe (non-maximal but large θ12)close to equal mixing of νµ and ντ (θ23 ≈ 45)

I we know the sign of ∆m221 (matter effect in sun) but not of ∆m2

31I θ13: νe component of ν3

T. Schwetz 13

3-flavour oscillations Recent developements on θ13

Effects of θ13

1. subleading effects in solar/KamLAND/atmospheric oscillations

2. transitions of νe involving ∆m231:

2.1 νe disappearance at reactors with L ' 1 km

“clean” measurment of θ13: P ≈ 1− sin2 2θ13 sin2(∆m231L/4E )

2.2 νµ → νe transitions at accelerator experiments

complicated function of all osc parameters (CP phase δ)

T. Schwetz 14


Effects of θ13

1. subleading effects in solar/KamLAND/atmospheric oscillations

2. transitions of νe involving ∆m231:

2.1 νe disappearance at reactors with L ' 1 km“clean” measurment of θ13: P ≈ 1− sin2 2θ13 sin2(∆m2

31L/4E )2.2 νµ → νe transitions at accelerator experiments

complicated function of all osc parameters (CP phase δ)

simulation: assume sin2 2θ13 = 0.1, δ = π/2

Huber, Lindner, TS, Winter, 09T. Schwetz 14


θ13 till June 2011

I sin2 θ13 . 0.04 (3σ) from global data (dominated by CHOOZ)

I weak indications for θ13 > 0 @ 1.8σ global fit(solar/KamL and MINOS/SK)TS, Tortola, Valle, 08, 1103; Fogli et al, 08; Gonzalez-Garcia, Maltoni, Salvado, 10

T. Schwetz 15


T2K data on νµ → νe appearance

search for νµ → νe oscillationswith L = 295 km andEν ' 0.7 GeV

K. Abe et al., 1106.2822

6 events obs1.5± 0.3 expected for θ13 = 02.5σ indication for θ13 > 0

T. Schwetz 16


Recent data on νµ → νe appearance

I T2K: 6 events obs (1.5± 0.3 expected for θ13 = 0)2.5σ indication for θ13 > 0 T2K, 1106.2822

I MINOS: 62 events obs (49.6± 7.0± 2.7 expected for θ13 = 0)consistent with θ13 = 0 MINOS, 1108.0015

!

0 0.025 0.05 0.075 0.1sin2θ13

-1

-0.5

0

0.5

1

δ / π

!

0 0.025 0.05 0.075 0.1sin2θ13

68%, 90%, 1 dof

NH

68%, 90%, 1 dof

IH

T2KMINOS

MINOS

T2K

T. Schwetz 17


Global data on θ13 TS, Tortola, Valle, 1108.1376

sin2 θ13 = 0.013+0.007−0.005 sin2 θ13 = 0.016+0.008

−0.006

θ13 = 0 : ∆χ2 = 10.1 (3.2σ)

similar results by Fogli et al, 1106.6028; Maltoni @ EPS11T. Schwetz 18


New generation of θ13 reactor experiments

T. Schwetz 19


New generation of θ13 reactor experiments

DC: 1112.6353 101d 4121ev sin2 2θ13 = 0.086± 0.041± 0.030 (1.9σ)DB: 1203.1669 55d 10416ev sin2 2θ13 = 0.092± 0.016± 0.005 (5.2σ)RE: 1204.0626 229d 17102ev sin2 2θ13 = 0.113± 0.013± 0.019 (4.9σ)

naive comb.: sin2 2θ13 = 0.098± 0.013 (χ2 = 0.6/2 dof)

Gonzalez-Garcia, Maltoni, Salvado, TS, in prep.

T. Schwetz 20


Global fitwith SBL data:

sin2 θ13 = 0.022+0.0033−0.0030

sin2 2θ13 = 0.086± 0.012θ13 = (8.5+0.62

−0.61)

6.9σ significance

without SBL data using2011 flux pred.:

sin2 θ13 = 0.026+0.0034−0.0032

sin2 2θ13 = 0.101+0.013−0.012

θ13 = (9.3± 0.59)

8.0σ significance

Gonzalez-Garcia, Maltoni, Salvado,

TS, in prep.

T. Schwetz 21

3-flavour oscillations Comments on lepton mixing pattern

CKM versus PMNSQuark mixing:

UCKM =

1 ε ε

ε 1 ε

ε ε 1

Lepton mixing:

UPMNS =1√3

O(1) O(1) εO(1) O(1) O(1)O(1) O(1) O(1)

10-3 10-2 10-1 100

sinθij

13

23

12

leptons (PMNS)

quarks (CKM)

3σ errors

T. Schwetz 22


Symmetry versus anarchy?

Are lepton mixing angles “special”?

Example: Tri-bimaximal mixing: Harrison, Perkins, Scott, hep-ph/0202074

UTBM =

√

2/3 1/√

3 0−1/

√6 1/

√3 1/

√2

1/√

6 −1/√

3 1/√

2

Lots of activity in the literature on predicting special flavour structure byimposing symmetries (discrete, non-abelian, An, Sn, Zn, Dn,...)

enforce relations such as:|Uµ3| = |Uτ3||Ue3| = 0|Ue2| = |Uµ2| = |Uτ2|

Is this approach still attractiveif θ13 is large?

T. Schwetz 23


Symmetry versus anarchy?

Maybe the mixing angles are just random numbers? Murayama et al.

probability of more special pattern is 44% deGouvea, Murayama, 1204.1249

T. Schwetz 24

3-flavour oscillations Open questions

Open questions

I How close is θ23 to 45?

I Is the neutrino mass ordering normal or inverted?INVERTEDNORMAL

[mas

s]2

3ν

ν2

ν1

ν2ν1

ν3

νe

µν

ντ

look for matter effect in transitions involving ∆m231

I Is there CP violation in the lepton sector?search for difference in να → νβ and να → νβ oscillations

Current LBL experiments: T2K, NOvAActive investigations towards a facility beyond thoseSuperbeam (LBNE, LBNO, HyperK), Beta Beam, Neutrino Factoryrecent discovery of “large” θ13 is changing this discussion

T. Schwetz 25


Majorana nature of neutrinos

Maybe lepton mixing is so different because neutrinos are Majorana?

Search for neutrinoless double beta decay: (A, Z ) → (A, Z + 2) + 2e−

⇒ violation of lepton number by 2 units

strong indication of Majorana nature of neutrinos Schechter, Valle, 1982; Takasugi, 1984

-5 -4 -3 -2 -1 0Log HmMIN @eVDL

-3

-2

-1

0

Log

HÈ<m>È@eVD

L sin2Θ13 = 0.03 ± 0.004

NH

IH QD

-5 -4 -3 -2 -1 0Log HmMIN @eVDL

-3

-2

-1

0

Log

HÈ<m>È@eVD

L

T. Schwetz 26


Absolute mass of neutrinos

I Kinematical mass measurments(beta decay spectrum endpoint)

KATRIN sensitivity to∑

i |Uei |2mi ∼ 0.2 eV

I Cosmology (HDM)free streaming of neutrinos reduces matter power at small scales

current limits around∑

i mi . 0.1 eV

T. Schwetz 27


Is the standard 3-neutrino scenario the end of the story?

T. Schwetz 28

Sterile neutrinos

Outline

Introduction



Conclusions

T. Schwetz 29

Sterile neutrinos

Sterile neutrinos at the eV scale

Sterile neutrinos are genericin models for neutrino mass(though typically at muchhigher scales).

Why not assume that someof them have masses at theeV scale?

T. Schwetz 30

Sterile neutrinos

Hints for eV neutrinos from νµ → νe searches

I LSND νµ → νe , 87.9± 22.4± 6.0 excess eventsP = (0.264± 0.067± 0.045)% ∼ 3.8σ away from zero

can be explained by oscillations with ∆m2 ∼ 1 eV2 and small mixing

not confirmed by any other experiment so-far

I KARMEN νµ → νe , tight constraint on LSND region(slightly smaller L/E than LSND)

I MiniBooNE νµ → νeE > 475 MeV: no excess, E < 475 MeV: ∼ 3σ excess

I MiniBooNE νµ → νe , inconclusiveconsistent with MBν as well as with LSND in 2ν framework

T. Schwetz 31

Sterile neutrinos The reactor anomaly

New reactor flux calculations

I to predict the νe flux from nuclear reactors one has to convert themeasured e− spectra from 235U, 239Pu, 241Pu into neutrino spectraSchreckenbach et al., 82, 85, 89

I recent improved calculation Mueller et al., 1101.2663 yields∼ 3% higher fluxes

I confirmed by independent calculation P. Huber, 1106.0687

T. Schwetz 32


New reactor flux calculations

data from short-baseline reactorexperiments:

µ = 0.927± 0.023

2.9σ away from 1

Mention et al, 1101.2755 (2012 upd)

T. Schwetz 33


New reactor fluxes and reactor data

Mention et al., 1101.2755 (2012 upd)

I non-zero θ13 can reduce flux at L & 1 km but not shorter baselinesI sterile neutrino with ∆m2 ∼ 1 eV2 can account for rate reduction at

L & 10− 100 mI systematic error...?

T. Schwetz 34


Reactor data and sterile neutrinos

3 4 5 6 7 8E

pos [MeV]

0.8

0.9

1

1.1

obse

rved

/ pr

edic

ted

rate

3 4 5 6 7 8E

pos [MeV]

0.9

1

Bugey3 15 m Bugey3 40 m

Bugey4

χ2

no osc = 59.0/69

χ2

3+1 = 50.1/67

χ2

3+2 = 46.5/65

10-2

10-1

100

sin22θ

react

10-1

100

101

∆m2 41

[eV

2 ]

90%, 99% CL (2 dof)

curves: old fluxescolors: new fluxes

∆m241 [eV2] |Ue4| ∆m2

51 [eV2] |Ue5| ∆χ2(no osc)3+1 1.78 0.151 8.5 (98% CL 2 dof)3+2 0.46 0.108 0.89 0.124 12.1 (98% CL 4 dof)

bounds on Ue4,5 become “preferred regions” with new reactor fluxesMention et al., 11; Kopp, Maltoni, TS, 11

T. Schwetz 35


The Gallium anomaly

callibration data in galliumsolar neutrino experimentsνe +71 Ga →71 Ge + e−

ratio of measured topredicted rate:

RBahcall = 0.86± 0.05 (2.8σ)

RHaxton = 0.76± 0.09 (2.7σ)

Acero, Giunti, Laveder, 0711.4222; Giunti, Laveder, 1006.3244

T. Schwetz 36

Sterile neutrinos Global sterile neutrino fit

Can we fit all this in a 3+1 (or 3+n) scheme3+1 νµ → νe appearance

Pµe = sin2 2θapp sin2 ∆m241L

4Esin2 2θapp = 4|Ue4|2|Uµ4|2

3+1 νe and νµ disappearance

Pαα = 1− sin2 2θdis sin2 ∆m241L

4Esin2 2θdis = 4|Uα4|2(1− |Uα4|2)

3+1: constraints from νe (νµ) disappearance experiments on Ue4 (Uµ4)imply that appearance mixing angle is quadratically suppressed

3+2: phase δ ≡ arg(

U∗e4Uµ4Ue5U∗

µ5

)→ CP violation

Karagiorgi et al. 06; Maltoni, TS 07

BUT: constrain |Uei | and |Uµi | (i = 4, 5) from disappearanceto be reconciled with appearance amplitudes |UeiUµi |

T. Schwetz 37


Limits on Uµ4

H

10-3 10-2 10-1

|Uµ4|2

10-2

10-1

100

101

∆m2 41

[eV

2 ]

atmospheric

CDHS

Kopp, Maltoni, TS, in prepMiniBooNE, 1106.5685

sin2 2θ = 4|U2µ4|(1 − |U2

µ4|)

I νµ disappearance CDHSI atmospheric neutrinos Bilenky, Giunti, Grimus, TS 99; Maltoni, TS, Valle 01

I MINOS NC data 1001.0336, 1104.3922

I additional constraints from MiniB νµ(νµ) at ∆m2 & 1 eV2

T. Schwetz 38


3+1 global fit

10-4

10-3

10-2

10-1

sin22θ

SBL

10-1

100

101

∆m2 41

[eV

2 ]

99% CL (2 dof)

LSND + MBν−

MBνKARMENNOMAD

disappearance90, 99% CL

I no CP violation → LSND+MBν versus MBν

I despite relaxed constraints on Ue4 no improvement of global 3+1 fitI LSND+MBν versus rest: χ2

PG = 21.5(24.2) for new (old) flux→ compatibility of less than 10−5

T. Schwetz 39


3+2 global fit Kopp, Maltoni, TS, PRL 11

H

H

0.1 1 10∆m

241

0.1

1

10

∆m2 51

0.1 1 100.1

1

10

90%, 95%, 99%, 99.73% CL (2 dof)

3+2

1+3+1

some improvement in the fit:

I ∆χ2(old vs new fluxes)3+2 = 11.1

I ∆χ2 (3+1 vs 3+2) = 11.2(97.6% CL, 4 dof)6.3 for old flux

∆m241 |Ue4| |Uµ4| ∆m2

51 |Ue5| |Uµ5| δ/π χ2/1303+2 0.47 0.128 0.165 0.87 0.138 0.148 1.64 110.13+2’ 0.47 0.117 0.201 1.70 0.151 0.101 1.39 114.43+2’ 1.00 0.133 0.163 1.60 0.122 0.079 1.48 114.43+2’ 0.90 0.123 0.163 6.30 0.135 0.091 1.67 115.0

1+3+1 0.47 0.129 0.154 0.87 0.142 0.163 0.35 106.1

T. Schwetz 40


There is severe tension in the 3+2 fit

Giunti, Laveder, 1109.4033

T. Schwetz 41


There is severe tension in the 3+2 fit

LSND+MB(ν) vs rest appearance vs disapp.old new old new

χ2PG/dof 25.1/5 19.9/5 19.9/4 14.7/4PG 10−4 0.13% 5× 10−4 0.53%

adding MINOS NC Kopp, Maltoni, TS, work in prep.

χ2PG/dof 30.0/5 24.8/5 24.7/4 19.5/4PG 10−5 10−4 5× 10−5 6× 10−4

I explanation of appearance signal requires Uei and Uµi (i = 4, 5)I no hint for oscillations seen in νµ disappearance⇒ constraints on Uµi in tension with signals

I MINOS NC data makes compatibility worse by one order of magnitude

T. Schwetz 42


Summary sterile global fit

I If we assume that the 3+n oscillation scenario is correct at least oneof the experiments is “mis-interpreted”.

I If we neglect LSND, the hint for νe disappearance from the reactorand Gallium anomalies remains (relies on complicated theoreticalcalculations, uncertainties difficult to estimate)

I If we stick to LSND, probably we have to discard more than oneexperiment (several experiments constrain νµ disappearance)

T. Schwetz 43

Sterile neutrinos

eV sterile neutrinos and cosmology

Hamann et al., 1006.5276

68, 95, 99% CL

I CMB, SDSS, HST: prefer some extra radiation, but limit on HDMexcludes two eV-scale neutrinos

I BBN: Ns < 1.2 (95% CL) Mangano, Serpico, 1103.1261

T. Schwetz 44

Sterile neutrinos

eV sterile neutrinos and cosmology

How to accommodate eV sterile neutrinos with cosmology?

I invent a mechanism to avoid thermalization(large chemical potential?)

I assume very low re-heating temperature (dangerously close to BBN)

I Hamann, Hannestad, Raffelt, Wong, 1108.4136

I limit on neutrino mass (HDM) can be evaded by allowing extraradiation ∆Nml ' 1− 2 and/or DE equation of statew < −1 Elgaroy, Kristiansen, 1104.0704

I BBN constraints on extra radiation can be avoided by introducing achemical potential of νe .

I modifies other cosmological parameters, e.g. ΩCDM (+20%-75%)

⇒ requires substantial modification of standard cosmology

T. Schwetz 45

Sterile neutrinos

More exotic ideas

I 3-neutrinos and CPT violation Murayama, Yanagida 01;

Barenboim, Borissov, Lykken 02; Gonzalez-Garcia, Maltoni, TS 03

I 4-neutrinos and CPT violation Barger, Marfatia, Whisnant 03

I Exotic muon-decay Babu, Pakvasa 02

I CPT viol. quantum decoherence Barenboim, Mavromatos 04

I Lorentz violation Kostelecky et al., 04, 06; Gouvea, Grossman 06

I mass varying ν Kaplan,Nelson,Weiner 04; Zurek 04; Barger,Marfatia,Whisnant 05

I shortcuts of sterile νs in extra dim Paes, Pakvasa, Weiler 05

I decaying sterile neutrino Palomares-Riuz, Pascoli, TS 05; Gninenko 10

I 2 decaying sterile neutrinos with CPVI energy dependent quantum decoherence Farzan, TS, Smirnov 07

I sterile neutrinos and new gauge boson Nelson, Walsh 07

I sterile ν with energy dep. mass or mixing TS 07

I sterile ν with nonstandard interactions Akhmedov, TS 10

most of these ideas

T. Schwetz 46

Sterile neutrinos

More exotic ideas

I 3-neutrinos and CPT violation Murayama, Yanagida 01;













most of these ideas involve sterile neutrinos

T. Schwetz 46

Sterile neutrinos

More exotic ideasI 3-neutrinos and CPT violation Murayama, Yanagida 01;













most of these ideas have problems with some data

T. Schwetz 46

Sterile neutrinos

Many ideas to test eV sterile neutrinos experimentally

I radioactive source experiments (e.g., in Borexino, SNO+) Cribier et al,

1107.2335; Garvin et al, 1006.2103; Vergados, Novikov, 1006.3862; Grieb, Link, Raghavan, hep-ph/0611178,...

I several ideas at FNAL (MINOS+, MicroBooNE, MiniBooNEextensions, very-low-E NuFact) B. Louis @ NuFact11

I ICARUS at CERN PS C. Rubbia et al. 0909.0355

I experiments with ∼100 kW proton synchrotronsConrad, Shaevitz 09; Huber, Agarwalla 10; Agarwalla, Conrad, Shaevitz, 11

I signatures in IceCube (Deep Core)Nunokawa, Peres, Zukanovich, hep-ph/0302039; Coubey, 0709.1937; Razzaque, Smirnov, 1104.1390, 1203.5406

I 2011 sterile neutrino workshops: LNGS, Italy (May),FNAL, USA (May), Virginia Tech, Blacksburg, USA (2011)

I White paper on sterile neutrinos 1204.5379

T. Schwetz 47

Conclusions

Outline

Introduction



Conclusions

T. Schwetz 48

Conclusions

Conclusions

I the bulk of data on neutrino oscillations is fitted perfectly within thethree-flavour framework, and we have evidence for oscillatorybehaviour of the survival probablility as function of neutrino energy

I recent results from reactor epxeriments (DoubleChooz, DayaBay,RENO) + T2K νe appearance establish non-zero value the lastunknown mixing angle θ13 ' 9 (not far from the previous upperbound)

I there are intriguing hints for sterile neutrinos at the eV scale:LSND, reactor anomaly, Gallium anomaly, cosmology?BUT: no consistent picture has emerged sofar

Thank you for your attention!

T. Schwetz 49

Kosmologietag Bielefeld, 3 May 2011 Thomas Schwetz-Mangold · 2012. 5. 7. · News from neutrinos...

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