Revisiting Science Case for Auger-North

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Revisiting Science Casefor Auger-North
Katsushi Arisaka
University of California, Los Angeles Department
of Physics and Astronomy arisaka_at_physics.ucla.edu
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Outline

• What have we learned from Auger-South?
• Energy Spectrum
• Absolute Energy Scale and Flux
• GZK Cutoff Structure
• Composition
• Hadronic Mass Composition
• Photon Flux Limit
• Anisotropy
• Small Scale Auto-Correlation
• Correlation with Astronomical Objects
• BL Lac, TeV Blazar, Neutron Star, GRB
• What to do on Auger-North?
• Science Case
• Detector Optimization

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UCLA Auger Group over Summer 2005

• Physicists
• Katsushi Arisaka Professor
• William Slater Professor
• Arun Tripathi Research Scientist Energy
  Spectrum
• Graciela Gelmini Professor (Theory) Gamma Limit
• Alex Kusenko Professor (Theory)
• Oleg Kalashev Research Scientist (Theory) Energy
  Spectrum
• Grad Students
• Tohru Ohnuki PhD (on July 27) Clustering
• David Barnhill PhD (on October 13) Photon Limit
• Joong Lee 5th year grad. Energy Spectrum
• Pedram Boghrat 5th year grad. Clustering, BL
  Lac
• Matt Healy 4th year grad. Gamma/Composition
• Antoine Calvez 1st year grad. Clustering, BL
  Lac
• Undergrad Students
• Eitan Anzenber Undergrad. (UCSC) GRB w/ Swift
  data
• Adrian Cheng Undergrad. Thread-like clustering

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Energy Spectrum

• Energy Determination
• GZK Cutoff Structure

Arun Tripathi et al, GAP2005-061
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Strategy of UCLA Analysis

• Coverage of the Entire Phase Space by MC
• Typically 20 events per each condition
• De-convolution of Physical Processes

Parameter Values No. Values
Shower Simulator AIRES, CORSIKA 2
Hadronization Model QGSJET, , QGSJET II, SIBYLL 3
Low Energy Hadronization FLUKA, GEISHA (in CORSIKA) 2
Detector Simulation G4FAST, G4LUT, Full G4, SDSIM 4
Primary Particle Kind Proton, Iron, Photon 3
Energy ( E ) 1, 3.1, 10, 31, 100 EeV 5
Zenith (? ) 0, 25, 36, 45, 53, 60, 66, 72, 84o 9
Reconstruction CDAS, OG (DPA), UCLA 3
Beta Fixed, Float 2
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S(1000) vs. Sec(?)
47.0VEM
35.4VEM
SD based CIC
Iron
Proton
60o
45o
30o
38o
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Model Dependence of S(1000) of Proton
60o
45o
30o
38o
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Model Dependence of S(1000) of Proton
QGS (Aires)
QGSFluka (Corsika)
QGSGeisha (Corsika)
QGSIIGeisha (Corsika)
Sys. Error lt 10
Sibyll (Aires)
45o
30o
38o
60o
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Summary of S(1000) at 38o and 10 EeV
FD (Event by Event)
FD (Mixed Shower)
47.0
FD Average
Proton, QGSJET, OG Proton, QGSJET,UCLA Proton,
SIBYLL, OG Proton, SIBYLL, UCLA Iron, QGSJET,
OG Iron, QGSJET,UCLA Iron, SIBYLL, OG Iron,
SIBYLL, UCLA SD Average
35.4
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Systematic Uncertainty (at 100 EeV)
FDCIC
SDCICMC
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Summary of Absolute Energy

• FD energy and SD energy differ by 30.
• No simple to change the SD energy to match the
  FD.
• SD energy could be 10 too high, if iron
  dominant.
• FD based method is currently limited by
• Poor statistics Systematic errors at 100 EeV is
  gt 40.
• Non trivial calibrations.
• Absolute photon yield
• Atmospheric correction
• Detector calibration.
• FD energy still seems 20 too low.

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Data Set for Energy Spectrum

• Data Period
• Jan 2004 Sep 2005
• UCLA Aperture Estimate
• 2297 km2 yr sr
• AGASA 1619 km2 yr sr
• HiRes 5000 km2 yr sr
• Obtained from a simple but robust method
  developed at UCLA.
• Agrees with a much more detailed calculation.

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Energy Spectrum ? E
SDCICMC
FDCIC
90 CL
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Energy Spectrum ? E3
FDCIC
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Energy Spectrum ? E3
SDCICMC
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Energy Spectrum ? E3
SDCICMC
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Energy Spectrum ? E3
FDCIC
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Theoretical Prediction (? dependence)
FDCIC
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Theoretical Prediction (Emax dependence)
FDCIC
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Theoretical Prediction (m dependence)
FDCIC
Flux (1z)3m
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Theoretical Prediction (zmin dependence)
FDCIC
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Theoretical Prediction (? dependence)
SDCICMC
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Theoretical Prediction (Emax dependence)
SDCICMC
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Theoretical Prediction (m dependence)
SDCICMC
Flux (1z)3m
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Zenith Dependence of Energy Spectrum
SDCICMC
30 45o
0 30o
45 60o
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North-South Effect
SDCICMC
South
North
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Summary of Energy Spectrum

• Energy spectrum, based on SDMCCIC, is
  consistent with the theoretical prediction of the
  GZK cutoff.
• Injection spectrum of 1/E2.6.
• Evolution factor not required.
• A hint of extra post-GZK events?
• However, Energy spectrum, based on FDCIC, is not
  fully consistent with the GZK cutoff.
• Cutoff energy seems too low.
• Too flat above cutoff energy.
• We could use the predicted GZK shape for the
  absolute energy calibration.
• It supports SDMCCIC, and disfavors FDCIC
  method.

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Composition

• Hadronic Mass Composition
• Gamma Flux Limit

David Barnhill, GAP2005-082 (PhD Thesis)
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S(1000) vs. Sec(?)
Iron
Proton
SD based CIC
Photon
60o
45o
30o
38o
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S(1000) MC/CIC vs. sec(?) at 10 EeV
Minimum Sys. Error
Iron (QGS)
Iron (Sibyll)
Proton (QGS)
Sensitive to Xmax
Sensitive to Muon Richness
Proton (Sibyll)
60o
45o
30o
38o
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S(600) MC/CIC vs. sec(?) at 10 EeV
Minimum Sys. Error
Iron (QGS)
Iron (Sibyll)
Proton (QGS)
Sensitive to Xmax
Sensitive to Muon Richness
Proton (Sibyll)
60o
45o
30o
38o
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S(r)MC/S(r)FDCIC vs. r (Zenith 36o)
Minimum Sys. Error
Iron (Sibyll)
Iron (QGS)
Proton (QGS)
Sensitive to Muon Richness
Proton (Sibyll)
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Muon Richness vs. Xmax
Iron/QGSJET
Iron/SIBYLL
Proton/QGSJET
Proton/SIBYLL
Gamma/QGSJET
Gamma/SIBYLL
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Rise Time vs. Sec(?)
Photon
Proton
Real Data
Iron
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Curvature vs. Sec(?)
Iron
Proton
Real Data
Photon
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?2 vs. Energy (Rise Time)
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?2 vs. Energy (Curvature)
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?2 vs. Energy (Rise Time Curvature)
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Photon Detection Efficiency
30EeV
20EeV
Limited analysis to E gt 20EeV 30o lt Zenith lt 60o
10EeV
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? of Rise Curvature vs. ? of Time (Under Photon
Assumption)
Proton MC
Gamma MC
(Gamma MC)
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? of Rise Curvature vs. ? of Time (Under Photon
Assumption
50 lt Elt 79 EeV
Real Data
Gamma MC
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Flux ? E with Photon Limit
SDCICMC
FDCIC
FD
Photon 90 CL Limit
SD
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Flux ? E3 with Photon Limit
Auger Energy based on FDCIC
SD
Photon 90 CL Limit
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Flux ? E3 with Photon Limit
Auger Energy based on SDCIC
SD
Photon 90 CL Limit
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Summary of Photon Flux Limit

• The combination of the following assumptions is
  disfavored.
• AGASA-like energy spectrum is correct.
• There is an extra Trans-GZK component.
• These Trans-GZK events are from the decay of
  Super Heavy Dark Matters.
• Most likely
• No Top-down component, at least, majority of
  UHECR are the Bottom-ups.

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Anisotropy

• Small-scale Auto-correlation
• Correlation with Astronomical Objects

Tohru Ohnuki , GAP2005-080 (PhD Thesis)
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Activities at UCLA

• Data sample
• January 2004 September 2005
• Direction reconstructed by CDAS
• Zenith coverage 45o, 60o, 75o, 85o.
• Energy determined by SDCICMC
• FDCIC based plots being processed.
• Systematic Studies
• Small angle Auto-correlation
• Correlation with Astronomical Objects
• BL Lac, TeV Blazar, Neutron Star, GRB
• Thread-like Clustering

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Angular Resolution
UCLA
CDAS
AGASA
HiRes Stereo
OG
Joong Lee et al, GAP2005-079
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Previously Claimed Correlations by AGASA/HiRes
Mrk421
H1426428
Triplet
Mrk501
1ES19596450
G.C.
1ES2344514
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Auger Sky Map (gt 10EeV, lt45o)
Energy by SDCICMC
G.C.
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Auger Sky Map (gt 10EeV, lt60o)
Energy by SDCICMC
G.C.
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Auger Sky Map (gt 10EeV, lt75o)
Energy by SDCICMC
G.C.
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Auger Sky Map (gt 10EeV, lt85o)
Energy by SDCICMC
G.C.
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Sky Map of Auger (gt10 EeV, lt85o)(with
correlations claimed by AGASA/HiRes)
Mrk421
H1426428
Triplet
Energy by SDCICMC
Mrk501
1ES19596450
G.C.
1ES2344514
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AGASA Auto-Correlation (Egt40EeV)
Triplet
G.C.
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Auger Auto-Correlation (gt 40EeV, lt85o)
G.C.
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Auger Auto-Correlation (gt 10EeV, lt60o)
G.C.
Triplet
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Auger Auto-Correlation (gt 10EeV, lt60o)
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Auger Auto-Correlation (gt 6EeV, lt60o)
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HiRes BL Lac Correlation
G.C.
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Auger BL Lac Correlation
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Auger BL Lac Correlation
Antoine Calvez et al, GAP2005-057
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Correlation with TeV Blazars
All 5 TeV Blazars
Mrk 501
Mrk 421
H1426428
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Correlation with Neutron Stars
Magnetar
Glitching Pulsar
Soft Gamma Repeater
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Summary of Science from Auger-South

• GZK cut-off seems to exist.
• Lorentz Invariance is valid.
• Cut-off energy may be lower than predicted?
• A hint of post GZK events??
• There is no gamma ray at all.
• Top-down scenarios are disfavored.
• Bottom-up should be the case.
• But no signature on the sky map yet.
• Iron dominant?
• Magnetic fields stronger than predicted??

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Auger-North

• Science Case
• Infill in Auger-South
• Auger-North Detector

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Science Case for North

• We must build even Larger Detector than
  previously thought.
• Super GZK events are fewer than AGASAs
  observation.
• But a hint of the excess above the GZK cutoff.
• Where is the real end point of the spectrum?
• Try to get Photons and Neutrinos from Top-down
  Mechanism and GZK interaction, if there is any.
• A window of the opportunity for Charged Particle
  Astronomy above 4?1019 eV.
• So far, no anisotropy.
• Again, we need a really big detector for high
  statistics.
• Northern sky seems different from Southern Sky!
• At least, AGASA and HiRes say so.

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Rich Physics and Astronomy
1021 eV
1020 eV
1019 eV
1018 eV
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Rich Physics and Astronomy
1021 eV
at Auger-North!
1020 eV
1019 eV
1018 eV
at Auger-South!
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Basic Concept of Hybrid SD
MC Simulation of 1019 eV Proton Shower
e?
10km
e?
27Xo 11?I
??
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S(1000)/E vs. X-Xmax (100EeV)
36o
25o
0o
45o
53o
??
60o
66o
?
e?
Arisaka et al, GAP2004-037
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?(540)/E vs. X-Xmax (100EeV)
?
25o
0o
36o
45o
53o
e?
60o
66o
??
Arisaka et al, GAP2004-037
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Summary of Hybrid

• FD Water Tank (Auger-like)
• Energy is determined by FD
• Composition/Model is determined by combination of
  Xmax in FD and Muon counting by SD
• FD Scintillator (TA-like)
• Energy is determined by both FD and Scintillator.
• Composition is determined by Xmax only.

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Hybrid-SD Detector
e? ??
Scintillator
Auger-Tank
? 50???
??
Muon Hodoscope
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Auger Original Region (3,120km2)
Auger-Tank x 1600
750m
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Infill Region (97km2)
25 Hybrid SD (Original Location)
75 additional Hybrid SD (Infill)
750m
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Case for Infill in Auger-South

• We are already limited by systematics below 30
  EeV.
• Absolute energy determination.
• Composition study.
• Both are strongly correlated.
• With modest additional Infill detectors on
  Auger-South, we can attack both problems.
• Water Tank Scintillator Muon Counter
• Such modification should have very high priority.
• Plan and develop now!
• Perhaps making the Infill by the last 100 tanks?

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Auger-North at Colorado
15.000km2
Infill
FD
SD 536m Square
10km
100M
SD 1.609km Square
122km
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Detector Size per Site
Spacing No. of Detector Area Coverage Energy Threshold Energy Resolution Angular Resolution
L NSD Stotal (at 1020eV) (at 1020eV)
Original Auger-S 1.5 km Triangle 1,600 3,120 km2 3x1018 eV 20 0.5 o
Auger-N 1.609 km Square 5,800 15,000 km2 5?1018 eV 20 0.5o
Infill Array 536 m Square 350 100 km2 5?1017 eV
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2? FD
30o
15o
10 km
40 km
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Comparison of Experiments
Exper-iment Method Covered Area Duty Factor Effective Aperture Energy Thres. Energy Resol. Angle Resol. Cost Start Year
Unit km2 km2str eV Deg. M -
Fly's Eye FD 300 10 100 1017 20 2o 0.5 1986
AGASA SD 100 100 250 1018 20 2o 1 1992
HiRes FD 3,000 10 1,000 1018 20 0.5o 5 1999
Auger -South SD 3,100 100 9,000 3x1018 20 1.0o 50 2005
Auger -South Hybrid 3,100 10 900 1018 15 0.5o 50 2005
Auger - North SD 15,000 100 45,000 5x1018 20 1.0o 100 2010
Auger - North Hybrid 3,100 10 900 1018 15 0.5o 100 2010
TA SD 800 100 2,000 3x1018 20 1o 20 2007
TA Hybrid 60 10 160 1018 15 0.5o 20 2007
EUSO FD 150,000 10 50,000 1019 30 2o 250 gt2012
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Integrated Sensitivity (at 1020 eV)