Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward...

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Upward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration ICRC 2005 Pune

Transcript of Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward...

Page 1: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Upward Showering Muons in Super-Kamiokande

Shantanu Desai /Alec HabigFor

Super-Kamiokande Collaboration

ICRC 2005 Pune

Page 2: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Upward Going Muons in Super-K

THRU

STOP

Eυ (GeV)

dΦ/d

logE

υ( 1

0-13 c

m-2

s-1

sr-1

)

ThrugoingStopping

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

1 10 102

103

104

105

Page 3: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Muon Energy loss as a function of Energy

Distribution asymmetric for each muon energies

Reasonably good agreement of Monte-Carlo with PDG

Ei

EfL

dE/dX = (Ei - E

f)/L

Aim of this analysis is only to separate a given muon into showering/non-showering

Muon energy (GeV)

< d

E/dX

(MeV

cm

2 g-1

) >

Average < dE/dX > from M.C.

Ionization LossRadiative Loss

Total Loss

1

10

10 2

1 10 102

103

104

105

Showering Muon

(Groom et al 03)

Non-Showering muon

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Muon track

PMT

dwat

Apply following correction for every PMT in Cherenkov Cone

qcorr

= qraw

dwat

exp(dwat

/Latten

)

-------------------------- F(θ)

where Latten

= Water attenuation length,

dwat

= Distance from PMT to point of

projection to µ track F(θ) = PMT acceptance + shadowing

Divide the muon track into 50 cm bins. For each bin, calculate average corrected charge and its error as follows:

Qcorri ��

1

N pmt qcorr

N pmt

where Npmt

= No of pmts within the given

projected distance corresponding to each bin

�Qcorri

2 �1

N pmt2 �

1

N pmt qcorr2

qraw

Corrections to raw PMT charge

Page 5: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Muon track

PMT

dwat

Apply following correction for every PMT in Cherenkov Cone

qcorr

= qraw

dwat

exp(dwat

/Latten

)

-------------------------- F(θ)

where Latten

= Water attenuation length,

dwat

= Distance from PMT to point of

projection to µ track F(θ) = PMT acceptance + shadowing

Divide the muon track into 50 cm bins. For each bin, calculate average corrected charge and its statistical error as follows:

Qcorri ��

1

N pmt qcorr

N pmt

where Npmt

= No of pmts within the given

projected distance corresponding to each bin

Corrections to raw PMT charge

�Qcorri

2 �1

N pmt2 �

1

N pmt qcorr2

qraw

Page 6: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Corrected Charge Distribution Comparison of ionizing vs showering muon

Projected Distance Along Track (m)

Mea

n co

rrec

ted

phot

o-el

ectr

ons

/ 0.5

m

0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14 16 18 20Projected Distance Along Track (m)

Mea

n co

rrec

ted

phot

o-el

ectr

ons

/ 0.5

m0

10

20

30

40

50

60

70

80

90

0 2 4 6 8 10 12 14 16 18 20

Muon Energy = 20 GeV Muon Energy = 10 TeV

dE/dX = 2.16 MeV/cm dE/dX = 8.5 MeV/cm

Both simulated muons have same entry point and direction

Page 7: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

for a ionizing muon as a functionof path-length

Variables used for showering/non-showering separation

�2��i�3

n�2

��Qcorri ��Qcorr

2 ��Qcorri

2 �

where �Qcorr �

�4

n�3

Qcorri ��Qcorr

i

2

�4

n�3

1��Qcorri

2

q l ���Qcorr and

����Qcorr �q l �

{Shape Comparison

Difference in averagecorrected charge ofgiven muon – samefor ionzing muon

(Average corrected charge averaged over entire muon length)

{

Absolute Corrected Charge Comparison

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log10 (Σ {(dE/dX)i- mean}2/dof)

No of

even

tsDataM.C.

0

100

200

300

400

500

600

0 0.5 1 1.5 2 2.5 3 3.5

DataMonte-Carlo

(∆m2 =0.002 sin2 2Θ =1.0)

[ mean qcorr - Q(L) ]

No of

even

ts

0

20

40

60

80

100

120

140

160

180

200

-4 -2 0 2 4 6 8 10

comparison

for data and monte-carlo

for data and monte-carloχ2

∆ comparison

Variables when appliedto 100yr upmu NEUT Monte-Carlo

Page 9: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

SHOWERING CUT USED

χ2 /DOF>20 and ∆>2.5

χ2/DOF >30 and ∆ >2.0

χ2 /DOF>50 and ∆>0.5

∆ > 4.5

OR

OR

ORTotal no of showering events = 5575 (out of 37301) in 100 year upmu NEUT Monte-carlo

χ2/DOF >40 and ∆ >1.0

Efficiency = 71 % where,

Efficiency = No of events Identified by algorithm --------------------------------------------- No of events with ∆ E / ∆ X > 2.85 MeV/cm

∆ E = Energy deposited by muon in inner detector

∆ X = Length of muon in inner detector

OR

Page 10: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

NEUTRINO ENERGY SPECTRA

Eυ (GeV)

dΦ/d

logE

υ( 1

0-13 c

m-2

s-1

sr-1

)

ShoweringNon-showeringStopping

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

1 10 102

103

104

105

<Eυ> ~ 1 TeV

<Eυ> ~ 100 GeV

<Eυ> ~ 10 GeV

Page 11: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Super-KamiokandeRun 2101 Sub 3 Ev 1523996-07-05:01:46:37 0013 dee4 0606

Inner: 10877 hits, 191405 pE

Outer: 249 hits, 863 pE (in-time)

Trigger ID: 0x0b

D wall: 1690.0 cm

Upward-Going Muon Mode

Charge(pe) >26.723.3-26.720.2-23.317.3-20.214.7-17.312.2-14.710.0-12.2 8.0-10.0 6.2- 8.0 4.7- 6.2 3.3- 4.7 2.2- 3.3 1.3- 2.2 0.7- 1.3 0.2- 0.7 < 0.2

0 500 1000 1500 20000

400

800

1200

1600

2000

0 500 1000 1500 20000

400

800

1200

1600

2000

Times (ns)

Event Display of upward showering muon

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Angular Resolution of showering muons

Shaded regioncontains 68 %of total area

Angular resolution = 1.25°

Thrugoing muons : Angular resolution ~ 1°

Stopping muons : Angular resolution ~ 1°

Angular resolution of Showering thrumus

Angle between precision fit and truth fit

No

of e

vent

s

0

50

100

150

200

250

300

350

400

0 1 2 3 4 5 6 7 8 9 10

µtrue

µfit

Page 13: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Zenith-angle distribution of showering muons

cosΘ

No o

f eve

nts

No Oscillation

∆m2 = 0.0025 sin2 2Θ =1.00

0

200

400

600

800

1000

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

Showering muons relatively insenstive to oscillation ==> For this dataset chi-square for null -oscillation should be very good fit

Page 14: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Background SubtractionApplied the showering algorithm to horizontal thrugoing muonwith 0 < cos(θ)< 0.08

Azimuth distribution of all showering muons

Φ (degrees)

No

of E

vent

s

(1) (2) (1)

1

10

10 2

10 3

0 50 100 150 200 250 300 350

19.48 / 14P1 1.702 0.8869P2 1.728 0.7089P3 65.17 10.86

cosΘ

Num

ber o

f Eve

nts Region (1) Φ < 60 , Φ > 240

Region (2) 60 < Φ < 240

10-1

1

10

10 2

10 3

-0.1 -0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08

Nbkgd

= 8.63 +12-5

for cos(θ)> -0.1 (Asymmetric distribution because of bump near horizon)

Fit to thin rock zenith angle distribution: f[cos(θ)] = p1+ exp [p2+p3 cos(θ)]

Page 15: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Showering Muon Oscillation Results

Best-fit (physical region) : χ2 = 4.68 / 7 dof for (∆m2, sin22θ) = (0.0104 eV2, 0.9)

Best-fit (null oscillation) : χ2 = 6.51/9 dof

Zenith angle comparisonat best fit point

Null oscillation normalized by livetime

cosΘ

No of

show

ering

muo

ns

0

10

20

30

40

50

60

70

80

90

100

-1 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0

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Projections of chi-square distributions for showering muons

Null oscillation allowed even at 68 % confidence level as expectedfor this high energy ν

µ with mean energy of ~ 1 TeV

0

2

4

6

8

10

10-4

10-3

10-2

∆m2 (eV2)

χ2 - χ2 m

in

68% C.L.90% C.L.99% C.L.

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1 1.2 1.4

sin22θ

χ2 - χ

2 min

68% C.L.90% C.L.99% C.L.

Page 17: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

Comparison with all upward thrugoing muons

0

2

4

6

8

10

10-4

10-3

10-2

∆m2 (eV2)

χ2 - χ2 m

in

68% C.L.90% C.L.99% C.L.

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8 1 1.2 1.4

sin22θχ2 -

χ2 min

68% C.L.90% C.L.99% C.L.

Best-fit : χ2 = 7.64 / 7 dof for (∆m2, sin22θ) = (0.0024 eV2, 0.96)

Best-fit at null oscillation : χ2 = 19.6/9 dof

Upward thrugoing muons sensitive to neutrino oscillation

Page 18: Upward Showering Muons in Super-Kamiokandebudoe.bu.edu/~shantanu/icrc05showering.sxi.pdfUpward Showering Muons in Super-Kamiokande Shantanu Desai /Alec Habig For Super-Kamiokande Collaboration

CONCLUSIONS � A sample of upward thrugoing muons which lose energy through radiative processes have been identified.

� Mean energy of parent neutrinos of upward showering muons ~ 1 TeV.

� 5575 showering muons in 100yr neut Monte-carlo and 309 events in 1679.6 days data

� Zenith angle distribution of upward showering muons consistent with null oscillations

� This dataset will now be used for oscillation analysis with all datasets by providing an extra energy bin at highest energies.

� A variety of astrophysical searches with upward showering muons done. Nothing found. (S. Desai thesis 2003. Also A. Habig poster)