PINGU and the Neutrino Mass Hierarchy - … · PINGU and the Neutrino Mass Hierarchy Ken Clark,...

PINGU and the Neutrino Mass

Hierarchy

Ken Clark, Penn State UniversityNeutrinos at the Forefront - Lyon, Oct 2012

Ken Clark - PSU Lyon, Oct 2012

Neutrino Oscillations

• Neutrino oscillations parametrized by

• mass squared differences Δm2ij

• mixing angles θij

• CP phase δCP

• Several questions remain

• What is the mass hierarchy (m3 > m1?)

2


Neutrino Mass Hierarchy

• Focus on the mass hierarchy in this talk

• We know Δm213 but not the sign

3


Experiments

• Several experiments targeting the mass hierarchy

• NOvA to start data collection soon

• R&D ongoing on Daya Bay II, LBNE, GLACIER, LENA, ORCA, PINGU


Theory - Atmospheric Neutrinos

• Why use atmospheric neutrinos?

• Not usually considered for use in precision parameter determination

• Broad range of baselines (~50 - 12500 km)

• Broad range of energies (~GeV - PeV)

5


Theory• Case for atmospheric neutrinos has been studied

previously (Phys. Rev. D 78, 093003 (2008) in particular although there are others)

• In essence this requires distinction between normal and inverted hierarchy in counts

• Hierarchy effects seen as neutrinos pass through matter

• ν oscillation probability is enhanced if hierarchy is normal

• ν̅ oscillation probability is enhanced if hierarchy is inverted

• and: ν, ν̅ have different cross sections

• Matter effects depend on size of θ13 which is now better defined

6


Starting Point Math

P⌫µ!⌫µ = 1�

cos

2✓

m13sin

22✓23 ⇥ sin

2

1.27

✓�m

231 +A+ (�m

231)

m

2

◆L

E

�

�sin2✓m13sin22✓23 ⇥ sin2

1.27

✓�m2

31 +A� (�m231)

m

2

◆L

E

�

�sin4✓23sin22✓m13sin

2

1.27(�m2

31)m L

E

�

• Interested primarily the νμ survival probability

• Note in particular the dependence on Δm231

7


Starting Point Plots

Energy (GeV)5 10 15 20 25 30 35 40 45

Probability

0

0.2

0.4

0.6

0.8

1

)µν→µνP(

Normal Hierarchy

Inverted Hierarchy

• Clear differences emerge between the hierarchies

• This is at a fixed zenith angle, ~150 degrees

8


Preliminary Reference Earth Model (PREM)

• Current “best guess” as to the variation of density in the Earth

• Been around a long time, still retains the preliminary name

MantleInnerCore

OuterCore


Matter effects

• Previous probabilities were just for one path length

• upgoing neutrinos experience effect of traveling through the Earth (or a fraction of it)

10

Radius (km)0 1000 2000 3000 4000 5000 6000

)3D

ensi

ty (g

/cm

4

6

8

10

12

PREM Earth DensityPREM Earth Density

MantleInnerCore

OuterCore


Matter Effects - I°

• At angles >146°

• ν pass through mantle and core

• parametric enhancement of oscillations take place

11

146°

Mantle InnerCore

OuterCore


Matter Effects

Length (km)0 2000 4000 6000 8000 10000 12000

Eart

h D

ensi

ty (g

/cm

^3)

0

2

4

6

8

10

12

14Normal Hierarchy

Inverted Hierarchy

°) with Travel Through the Earth - 20 GeV, 179µν→µνP(

)µν

→µν

P(

00.10.20.30.40.50.60.70.80.91

Length (km)0 2000 4000 6000 8000 10000 12000

Eart

h D

ensi

ty (g

/cm

^3)

0

2

4

6

8

10

12

14Normal Hierarchy

Inverted Hierarchy


)µν

→µν

P(

00.10.20.30.40.50.60.70.80.91

• These are almost directly upgoing

• Two different energies show magnitude of final effect

• This zenith dominated by parameteric resonance

12


Matter Effects - II

• At angles <146°

• ν pass through mantle only

• MSW enhances νμ to νe

13

Mantle InnerCore

OuterCore


Matter Effects

Length (km)0 1000 2000 3000 4000 5000 6000 7000

Eart

h D

ensi

ty (g

/cm

^3)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Normal Hierarchy

Inverted Hierarchy


)µν

→µν

P(

00.10.20.30.40.50.60.70.80.91

• Much less upgoing angles show MSW effects

• Note change in Earth density plot

14


Detection Method

• IceCube and DeepCore successfully detecting neutrinos for years

• IceCube: ~5160 PMTs in 1km3

• DeepCore: denser string and DOM spacing

• High efficiency PMTs


DeepCore Energy Range

• Detection threshold lowered to ~10 GeV in DeepCore

• Effective volume at trigger level increased below 100 GeV

GeV)10

Energy (Logµν1.0 1.5 2.0 2.5 3.0

(meg

aton

)ef

fect

ive

Vic

eρ

0

50

100

150

200DeepCore TriggerDeepCore Online FilterIceCube Trigger w/o DC


Step up to PINGU

• Add another 20 strings

• Denser string and DOM spacing

• Energy threshold lowers again

X (m)-100 -50 0 50 100 150 200

Y (m

)

-150

-100

-50

0

50

100PINGU Geometry V6 (Dozier)

IceCube

DeepCore

PINGU (HQE)

PINGU Geometry V6 (Dozier)


Step up to PINGU

• Add another 20 strings

• Denser string and DOM spacing

• Energy threshold lowers again

Energy (GeV)10 20 30 40 50 60 70

(MTo

n)ef

fV

0

2

4

6

8

10

12

14

PINGU v6 Effective Volume, R < 150m

> 0 hits

> 10 hits

> 20 hits

> 50 hits

> 100 hits

PRELIMINARY

PRELIMINARY


2 Dimensional Plotting

(Degrees)zθ120 130 140 150 160 170 180

E (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

) - Normal Hierarchyµν→µνP(

(Degrees)zθ120 130 140 150 160 170 180

E (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

) - Inverted Hierarchyµν→µνP(

(Degrees)zθ120 130 140 150 160 170 180

E (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

) - Normal Hierarchyµν→µνP(

(Degrees)zθ120 130 140 150 160 170 180

E (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

) - Inverted Hierarchyµν→µνP(

• Now we need to extend this to two dimensions to show the probability vs energy and zenith angle

20

E ν (

GeV

)E ν

(G

eV)

θz (Degrees) θz (Degrees)


DistinguishabilityStot =

s

(⌃ij

(N IHij �NNH

ij )2

NNHij

Stot =

s

(⌃ij

(N IHij �NNH

ij )2

NNHij

Stot =

s

⌃ij

(N IHij �NNH

ij )2

NNHij

• Use method outlined in arXiv:1205.7071 (Akhmedov, Razzaque and Smirnov)

• Essentially bin everything up and subtract the two hierarchies, scaled by the number of events in the Normal hierarchy bin

21


Simulations• Simulations now carried out using IceCube

MC structure

• Currently studying different PINGU geometries with different spacings

X (m)-100 -50 0 50 100 150 200

Y (m

)

-150

-100

-50

0

50

100IceCube

DeepCore

PINGU (HQE)

PINGU Geometry V3

X (m)-100 -50 0 50 100 150 200

Y (m

)

-150

-100

-50

0

50

100PINGU Geometry V5 (Cappelletti)

IceCube

DeepCore

PINGU (HQE)

PINGU Geometry V5 (Cappelletti)

X (m)-100 -50 0 50 100 150 200

Y (m

)

-150

-100

-50

0

50

100PINGU Geometry V6 (Dozier)

IceCube

DeepCore

PINGU (HQE)

PINGU Geometry V6 (Dozier)


Distinguishability Plots

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-2

0

2

4

6]1/2Distinguishability Metric [(IH-NH)/NH• Use our

simulations

• First use neutrino zenith angle and energy

• Shown without square root to illustrate pattern

24

PRELIMINARY



Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-2

0

2

4

6]1/2Distinguishability Metric [(IH-NH)/NH

• Matter effects due to MSW

25

PRELIMINARY



Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-2

0

2

4


• Primarily parametric oscillation effects in this region

26

PRELIMINARY



Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-2

0

2

4


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-3

-2

-1

0

1

2

3

4

• Then use muon zenith angle and neutrino energy

• Shown without square root to illustrate pattern

27

PRELIMINARY


Reconstruction

• Previous plots showed perfect detector resolution

• This (probably) won’t be the case

• Need to account for the reconstruction effects

• Add a gaussian “smearing” to the angles and energies

Ken Clark - PSU MANTS, Oct 2012

Detector Resolution

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-6

-4

-2

0

2

4


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-1.5

-1

-0.5

0

0.5

1

1.5

]1/2Distinguishability Metric [(IH-NH)/NH

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-1

-0.5

0

0.5

1


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8


0 GeV, 0°

2 GeV, 11.25°

3 GeV, 15°

4 GeV, 22.5°


Detector Resolution

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-6

-4

-2

0

2

4


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8


Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-0.6

-0.4

-0.2

0

0.2

0.4

0.6]1/2Distinguishability Metric [(IH-NH)/NH

0 GeV, 0°

2 GeV, 11.25°

3 GeV, 15°

4 GeV, 22.5°


Comparisons

• Following model in publication, used three different resolution pairs

• (2GeV,11.25°),(3GeV,15°),(4GeV,22.5°)

31

2 GeV, 11.25 Deg 3 GeV,15 Deg 4 GeV,22.5 Deg

Tota

l Sig

ma

Valu

e

0

5

10

15

20

25

Akhmedov et al

Neutrino Angle 1 Year

Muon Angle 1 Year

Calculated Total Sigma - PINGU 1 Year

PRELIMINARY


Systematics

• Studied several effects

1. Systematic energy shift +/-5%, +/-10%

2. Systematic angle broadening +/-5%, +/-10%

3. PREM quantities incorrect

• Core radii +/-5%, +/-10%

• Core densities +/-5%, +/-10%

32


Systematics - Illustrated

33

IH(T ) NH(T )

�2(IH(T ) : NH(T ))


Systematics - Illustrated

34

IH(T ) NH(T )

NH(S)

�2(IH(T ) : NH(S))

��2 = �2(IH(T ) : NH(S))� �2(NH(T ) : NH(S))

��

2> 0 ! ProperID

��

2< 0 ! WrongID

�2(NH(T ) : NH(S))


Energy Shift

• Systematic shift in energy has little effect

Run Length (years)1 1.5 2 2.5 3 3.5 4 4.5 5

2 χ Δ

20

25

30

35

40

° - Detector Resolution 2 GeV, 11.252χ Δ

No Systematic Shift

Energy Shift +5%

Energy Shift +10%

35

PRELIMINARY


Angle Broadening

• Not a systematic shift in zenith

• Misunderstanding of the detector resolution

Run Length (years)1 1.5 2 2.5 3 3.5 4 4.5 5

2 χ Δ

20

25

30

35

40

° - Detector Resolution 2 GeV, 11.252χ Δ

No Systematic Shift

Angle Broadening +5%

Angle Broadening +10%

36

PRELIMINARY


Next Steps

• Next objective is to include detector resolution effects properly using reconstructions

• Need to perform detailed analysis of systematics

• Start with quantification of best geometry

37


Timescale

March 2011

Early 2012

Begin simulation studies for 18-20 string

detector with threshold ~1GeV. Targeted Physics: neutrino

hierarchy, WIMPs, SN

Submit PINGU Proposal

Complete 1st DeepCore analyses.

Spring 2012

Winter 2016/17

Begin deploying PINGU

Winter 2017/18

Finish deploying PINGU including

R&D strings.Start data-taking early

2018

1st PINGU workshop -

NIKHEF

2nd PINGU workshop - Penn State

Jan 2012

Fall 2012

3rd PINGU workshop -

Erlangen

May 2012

Submit Letter

of Interest to NSF

Finish Detailed PINGU studies

Summer 2013

Fall 2013


Conclusion

• Determination of the neutrino mass hierarchy with atmospheric neutrinos appears feasible

• PINGU allows for this determination quickly in a cost effective implementation


Comparison

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

4

6

8

10

12

14

16

18

20

-4

-2

0

2

4


Things seem to compare reasonably well

41


Detector Resolution Plots

Cos(zenith angle)-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Ener

gy (G

eV)

2

4

6

8

10

12

14

16

18

20

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1


• Shown with detector resolution 2 GeV, 11.25°

42


Reality(-ish)

Zenith Angle (degrees)120 130 140 150 160 170 180

Ener

gy (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

) - Inverted Hierarchy (NuMu+NuMuBar)µν→µνP(

Zenith Angle (degrees)120 130 140 150 160 170 180

Ener

gy (G

eV)

5

10

15

20

25

30

35

40

45

50

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

) - Normal Hierarchy (NuMu+NuMuBar)µν→µνP(

• For νμ-like events we really get a mixture of νμ and νμ

43


Systematics• Can also add systematics on the simulated

data:

1. Apply detector resolution to both hierarchies (IH and NH)

2. Copy both hierarchies

3. Apply systematic shift to one copy for each

4. For each copy, calculate the significance of the opposite unshifted hierarchy and the same unshifted hierarchy

5. Subtract the same from the opposite value

44

PINGU and the Neutrino Mass Hierarchy - … · PINGU and the Neutrino Mass Hierarchy Ken Clark,...

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Transcript of PINGU and the Neutrino Mass Hierarchy - … · PINGU and the Neutrino Mass Hierarchy Ken Clark,...