Probing neutrino flavor transition mechanism with ultrahigh energy

astrophysical neutrinos

Probing neutrino flavor transition mechanism with ultrahigh energy

astrophysical neutrinos

賴光昶賴光昶長庚大學通識中心長庚大學通識中心

賴光昶賴光昶長庚大學通識中心長庚大學通識中心

2014 海峡两岸粒子物理与宇宙学研讨会

黃山，安徽， May 9th, 2014

KCL, T.-C. Liu and G.-L. Lin, PRD 82, 103003KCL, T.-C. Liu and G.-L. Lin, PRD 82, 103003KCL, T.-C. Liu and G.-L. Lin, PRD 89, 033002KCL, T.-C. Liu and G.-L. Lin, PRD 89, 033002

Astrophysical neutrinoAstrophysical neutrino

Neutrino flavor transitionNeutrino flavor transition

Neutrino signals in neutrino telescopesNeutrino signals in neutrino telescopes

Test of transition modelsTest of transition models

ErnieErnieErnieErnie

Bert, Bert, 1.04PeV1.04PeV Ernie, Ernie, 1.14PeV1.14PeV

Astrophysical Astrophysical neutrinoneutrino

Astrophysical Astrophysical neutrinoneutrino

““AstrophysicalAstrophysical”” means means

QQ-representation-representation

Standard oscillationStandard oscillation

Neutrino decayNeutrino decay

QQuantum decoherenceuantum decoherence

Pseudo-Dirac neutrinoPseudo-Dirac neutrino

Flavor transitionFlavor transitionFlavor transitionFlavor transition

Q-representationQ-representationQ-representationQ-representation

neutrino on Earthneutrino on Earth→φ=Pφ→φ=Pφ00←←neutrino at the sourceneutrino at the sourceφφ00==((φφ00((νe), ), φφ00((νμ), ), φφ00((ντ))=1/3))=1/3VV11+a+aVV22+b+bVV33

φφ==ϰϰVV11++ϱϱVV22++λλVV33

((ϰϰ, , ϱϱ, , λλ))TT==QQ((11//3, a, b3, a, b))TT

⇒⇒Q≡AQ≡A-1-1PAPA

Tri-bimaximal matrix, eigenvectors of TBMTri-bimaximal matrix, eigenvectors of TBM::

Q-representationQ-representationQ-representationQ-representation

Standard oscillationStandard oscillationStandard oscillationStandard oscillation

Neutrino decayNeutrino decayNeutrino decayNeutrino decay

NormalNormalhierarchyhierarchy

InvertedInvertedhierarchyhierarchy

Neutrino decayNeutrino decayNeutrino decayNeutrino decayThe heaviest and The heaviest and

middle states decay middle states decay

into the lightest into the lightest

one(j=1 or 3).-one(j=1 or 3).-dec1dec1

The heaviest state The heaviest state

decays into the middle decays into the middle

and lightest ones.-and lightest ones.-dec2dec2{{

εε11==coscos2ϑ2ϑ2323--((√√2/3)sin2/3)sinϑϑ1313, , εε22=(1/2)=(1/2)coscos2ϑ2ϑ2323--εε11

Quantum Quantum decoherencedecoherence

Quantum Quantum decoherencedecoherence

distance dependentdistance dependent

γγ→0 or →0 or d→d→∞∞, , QQdcdc=Q=Qoscosc

∆∆mmii22: the mass-squared difference between active and sterile states.: the mass-squared difference between active and sterile states.

Pseudo-Dirac Pseudo-Dirac neutrinoneutrino

Pseudo-Dirac Pseudo-Dirac neutrinoneutrino

∆∆mmii22 =∆m =∆m22

In the limit of L(z)/4EIn the limit of L(z)/4Eνν≫1/≫1/∆m∆mii22, , QQpdpd=1/2 =1/2

QQoscosc

Neutrino eventsNeutrino eventsNeutrino eventsNeutrino events

125m corresponds to the decay 125m corresponds to the decay length of a 2.5 PeV tau lepton.-length of a 2.5 PeV tau lepton.-dist. between stringsdist. between strings ≈ ≈1km corresponds to the decay 1km corresponds to the decay length of a 25 PeV tau lepton.-length of a 25 PeV tau lepton.-size of IceCubesize of IceCube1054.51541054.5154

ObservablesObservablesObservablesObservables

Case I:Eν<33PeV

Case II:Eν>33PeV

RI=ϕ(νμ)/(ϕ(νe)+ϕ(ντ))SI= ϕ(νe)/ϕ(ντ)

RII=ϕ(νe)/(ϕ(νμ)+ϕ(ντ))

SII= ϕ(νμ)/ϕ(ντ)

RI: track-to-shower ratio; RII:shower-to-track ratio

ObservablesObservablesObservablesObservables

ϕ0=(ϕ(νe), ϕ(νμ), ϕ(ντ))=1/3 V1+aV2+bV3.

for non-ντ sources, a=-1/3+b and let RII≡R.

flux conservation assumed

For pion and damped-muon sources

Statistical analysisStatistical analysisStatistical analysisStatistical analysisWe consider: We consider: • i=π, only pion sourcei=π, only pion source• i=π and µ, both pion i=π and µ, both pion and damped-muon and damped-muon sourcesource• σσ=10% assumed=10% assumed

G. Fogli, et al., PRD 86, G. Fogli, et al., PRD 86, 013012013012

Statistical analysisStatistical analysisStatistical analysisStatistical analysis

Legend:Legend:

• ✕✕: oscillation: oscillation

• ▵▵: dec1-n, : dec1-n, ▴▴:dec1-i:dec1-i

• ￮￮ , , ◇◇, , ⃞⃞: dec2-n: dec2-n

• ••, , ◆◆, , ▪▪: dec2-i: dec2-i

Pion sourcePion sourcePion sourcePion source

11σ σ regionregion 33σ σ regionregion

Pion sourcePion sourcePion sourcePion source

11σ σ regionregion 33σ σ regionregion

Pion sourcePion sourcePion sourcePion source11σ σ regionregion 33σ σ regionregion

Pion and Muon Pion and Muon sourcessources

Pion and Muon Pion and Muon sourcessources

11σ σ regionregion 33σ σ regionregion

Pion and Muon Pion and Muon sourcessources

Pion and Muon Pion and Muon sourcessources

11σ σ regionregion 33σ σ regionregion

Pion and Muon Pion and Muon sourcessources

Pion and Muon Pion and Muon sourcessources

11σ σ regionregion 33σ σ regionregion

SummarySummarySummarySummary

Neutrino astronomy has begun.Neutrino astronomy has begun.

28 astrophysical events observed28 astrophysical events observed

Flavor transitions can be probed:Flavor transitions can be probed:

QQ-representation -representation

Observable definedObservable defined

𝜒𝜒22-analysis performed-analysis performed