PINGU and the Neutrino Mass Hierarchy

Ken Clark (for the IceCube-PINGU collaboration)University of Toronto

K. Clark - ICHEP 2014

The IceCube Neutrino Telescope

2

K. Clark - ICHEP 2014

IceCube

3

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

Y (m

)-150

-100

-50

0

50

100 IceCube

PINGU Geometry - 26m String Spacing

125m

• 78 Strings

• 125m string spacing

• 17m DOM spacing

• Add 8 strings

• 75m string spacing

• 7m DOM spacing

• Add 20 strings

• 26m string spacing

• 5m DOM spacing10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV

IceCube

See “Astrophysical Neutrinos with the IceCube Detector” Saturday at 11:30

K. Clark - ICHEP 2014

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

Y (m

)-150

-100

-50

0

50

100 IceCubeDeepCore

PINGU Geometry - 26m String Spacing

IceCube + DeepCore• 78 Strings

• 125m string spacing

• 17m DOM spacing

• Add 8 strings

• 75m string spacing

• 7m DOM spacing

• Add 20 strings

• 26m string spacing

• 5m DOM spacing

4

75m

10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV

DeepCore IceCube

125m

K. Clark - ICHEP 2014

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

Y (m

)

-150

-100

-50

0

50

100 IceCube

DeepCore

PINGU

87 88 89 90 91 92 93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124 125 126

PINGU Geometry V15 (Ellett)

5

• 78 Strings

• 125m string spacing

• 17m DOM spacing

• Add 8 strings

• 75m string spacing

• 7m DOM spacing

• Add 40 strings

• 20m string spacing

• 5m DOM spacing

IceCube + DeepCore + PINGU

125m

20m

75m

10 TeV 1 EeV1 TeV100 GeV10 GeV1 GeV100 MeV10 MeV

DeepCorePINGU IceCube

K. Clark - ICHEP 2014

Mass Hierarchy Determination• Lower energy atmospheric neutrinos

provide the required large flux of neutrino events

6

Trigger Level

(per year)

Analysis Level

(per year)

νμ CC 86k 35k

νe CC 52k 26k

ν𝜏 CC 6.4k 2.7k

νX NC 17k 7.9k

“Tracks”

}“C

asca

des”

K. Clark - ICHEP 2014

Mass Hierarchy Determination• Experiments use the difference in MSW effect for ν and anti-ν• Combine with difference in ν and anti-ν cross-section• Variation in probability up to 20%

7

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 - 10 GeV, 179µν→µνP(

)µν

→µν

P(

00.10.20.30.40.50.60.70.80.91

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

°) with Travel Through the Earth - 6 GeV, 126µν→µνP(

)µν

→µν

P(

00.10.20.30.40.50.60.70.80.91

11

2

2

K. Clark - ICHEP 2014

Neutrino Oscillograms• The cross-

section and flux are different for νμ and νμ

• Counts will be derived from the essentially the addition of both graphs

8

K. Clark - ICHEP 2014

Mass Hierarchy Determination

• Difference in counts between hierarchies illustrates distinguishability

• Red areas indicate a surplus in IH, blue in NH

• Event selection, reconstruction not included here

9

Cascade-Like Events Track-Like Events

K. Clark - ICHEP 2014

Distinguishability

• Includes proper reconstruction of the events

10

K. Clark - ICHEP 2014

The Bottom Line

• Critically important question is how long does it take to make a measurement?

11

For more details see the PINGU LoI, arXiv:1401.2046

IH True

K. Clark - ICHEP 2014

Systematics• Impact on the final significance of several of the most

important shown here (study performed with each systematic turned off to determine the magnitude of the effect)

12

World Average +/- 1σ

World Average +/- 1σ

World Average +/- 1σ

+/-15%

+/-15%

+/-5%

Factor of E, σ(ν), σ(ν)

K. Clark - ICHEP 2014 13

Future of the NMH Measurement• several caveats

• median statistical outcome shown

• width indicates effect of main uncertainty (δCP, θ23)

• dates are current as of the manufacture of the plot

K. Clark - ICHEP 2014

Other Physics

14

• The lowered energy threshold also facilitates several other fields of study

• muon neutrino disappearance

• maximal θ23 measurement

• neutrino tomography

• lower energy dark matter

• neutrino mass hierarchyFor more details see the PINGU LoI, arXiv:1401.2046

K. Clark - ICHEP 2014

PINGU Advantages• Use of IceCube deployment techniques

and similar hardware reduces risk• Could be quick (2 years of acquisition/

fabrication, 2-3 years for deployment)• Relatively inexpensive• Fits well into the next phases of IceCube

extensions

15

K. Clark - ICHEP 2014

Conclusion• IceCube and DeepCore have been

very successful and have shown that particle physics is possible in ice

• PINGU will provide insight into the nature of the NMH for a very inexpensive total cost

• Many other physics topics addressed by the IceCube extensions

16

K. Clark - ICHEP 2014 17

K. Clark - ICHEP 2014

Backup

18

K. Clark - ICHEP 2014

Indirect Dark Matter Detection

• Possible to reach masses down to ~5GeV• Width indicates a variation of the detector

efficiency

19