Atmospheric neutrino selection

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

• goal: improve efficiencies for both E-2 and atmospheric neutrinos

• strategy– improved hitcleaning– track resolution (paraboloid fit)– zenith restricted fit– Phit/Pnohit fit– no neural networks (or similar)

Atmospheric neutrino selection

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Efficiency of New Analysis

• efficiency > 60% above 120°

atmo. neutrinos 45 % E-2 neutrinos 40 %

relative to L2

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Neutrino Candidates

Ndata NatmoMC

θ>90° 2021 1793

θ>110° 1194 1238

NatmoMC: ± 25%

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Effective Area

• zenith angle dependence

newstd.

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Atmospheric Neutrinos

• neutrino-effective area for energies above 50 GeV

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Corrected Zenith Angle Spectrum

• account for acceptance and oscillations

)GeV(

)km()eV(27.1sin2sin1 222

M2

E

LmP

232 eV104.2 m12sin M

2

SuperKamiokande:

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Restrictions on Δm2?

• neutrino flux relative to flux with 232 eV104.2 m

syst

emat

ic e

rror

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

What do we expect from 6 years?

• 10000 atmospheric neutrinos• study high energy• restrictions on alternative oscillation modells

Energy [TeV] < 0.1 0.1 - 0.3 0.3 - 1 1 - 3 3 - 10 >10

Events 900 2800 3200 1900 900 300

% 9 28 32 19 9 3

90% with energies from 0.1 – 10 TeV

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

MedianRes, Zenith (hard cuts z> 110°)

data 00-03 data 2000 data 2001 data 2002 data 2003

... years behave differently number of dead OM‘s is important!

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Lorentz invariance test

case 2: velocity eigenstates = mass eigenstates

case 1: velocity eigenstates = flavor eigenstates

examine 2 extreme cases:

Glashow - hep-ph/0407087

• neutrino species can have different maximal velocities v1, v2, v3 < c• velocity eigenstates rotated w.r.t. flavor eigenstates by v (and phase )

define Ecritical = Ec=sqrt(m²c / 2v)

E < Ec mass oscillation dominant Ec < E Lorentz violation dominant

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

AMANDA‘s range

survival probability for a for case 2 with Ec = 100 GeV

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Case 1: v = 0

hardly accessible for AMANDA

Ec = 1 GeV Ec = 10 GeV Ec = 100 GeV

Ec = 1 TeV Ec = 10 TeV Ec = 100 TeV

Ec = 1 PeV Ec = 10 PeV Ec = 100 PeV

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Case 2: v = /4

Ec = 1 GeV Ec = 10 GeV Ec = 100 GeV

Ec = 1 TeVEc = 10 TeV

Ec = 100 TeV

Ec = 1 PeV Ec = 10 PeV Ec = 100 PeV

well accessible for AMANDA for Ec< 1TeV

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Ec - cos() - plane

cos()

log

( E

c / G

eV )

exclusion regionscase 2:

(only 2002 data,preliminary)

90 % C.L. Ec ~ 102.5 = 316 GeVv/c ~ 1.2*10-26

99 % C.L. Ec ~ 102.2 = 158 GeVv/c ~ 4.6*10-26

Depends on assumed systematic errors (needs to be studied in detail)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Other studies

There are many (exotic) models around that can be tested:

Quantum decoherence extra dimensions

... and lots of other ideas

extensive ANTARES Monte Carlo study

... see Francis talk

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Additional plots (not shown)

Note: analysis 2000-2003 is very preliminary!

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Standard Analysis

Ndata = 470 NatmoMC= 402 ± 100

atmo. neutrinos 11 % E-2 neutrinos 28 %

• optimized for best sensitivity (E-2 – spectrum)• selected neutrinos 2002

• efficiencies

(for θ>90°)

relative to L2

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Efficiency of New Analysis

• efficiency > 60% above 120°

atmo. neutrinos 45 % E-2 neutrinos 40 %

relative to L2

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Neutrino Candidates

New analysis Standard analysis

12381194θ>110°

17932021θ>90°

NatmoMCNdata

312283θ>110°

437459θ>90°

NatmoMCNdata

NatmoMC: ± 25%

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Effective Area

E-2

• zenith angle dependence

newstd.

• energy dependence

new (for different spectra)

std.

new

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Atmospheric Neutrinos

• neutrino-effective area

• remaining background

contribution to systematic error ~10%

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Data 2000-2003

Level 5 data from Zeuthen 00-03 analysis

Level 6a fits with T.Becka‘s hit cleaning

Hard cuts:Ldiff>30 spaceangle(JAMS,phpnh)<10 spaceangle(pandel,phpnh)<100.4 > Smoothness > -0.4 MedianRes<5 „Soccer cut“

Softer cuts:Ldiff>25 spaceangle(JAMS,phpnh)<30 spaceangle(pandel,phpnh)<10Smoothness > -0.4 MedianRes<5 „Soccer cut“

pandel (seeded 32-Pandel)bayes (seeded 64-Bayes)PhPnh (seeded 10-PhPnh) ParabolaFit on PhPnh

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Data 2000-2003

3543319529182309softer cuts

z>90°

1819169014241075hard cuts z>90°

44,98541,37035,46830,955z>90°, flare<10, Irun

1679157413641075softer cuts z>110°

213204193197lifetime

11761138955746hard cuts z>110°

257,874238,475200,159149,404events L6a

2003200220012000year

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

GPS day vs. Zenith (no cuts)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Zenith vs. Cogz (no cuts)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

Zenith vs. Cogz (hard cuts z> 90°)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

MedianRes vs. Cogz (no cuts)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

MedianRes vs. Cogz (hard cuts z> 90°)

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (no cuts)

data 00-03 data 2000 data 2001 data 2002 data 2003

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (softer cuts z> 90°)

data 00-03 data 2000 data 2001 data 2002 data 2003

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (hard cuts z> 90°)

data 00-03 data 2000 data 2001 data 2002 data 2003

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

spaceangle(JAMS,phpnh), spaceangle(pandel,phpnh),Ldiff, Smoothness -- (hard cuts z> 110°)

data 00-03 data 2000 data 2001 data 2002 data 2003

Jens Ahrens and Thomas Becka, Atmospheric Neutrinos, Berkeley, March 2005

MedianRes, Zenith (hard cuts z> 90°)

data 00-03 data 2000 data 2001 data 2002 data 2003