New Cosmic Rays at the Highest Energies

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New Cosmic Rays at the Highest Energies
PANIC 05

GO SOX!
Angela V. Olinto AA, KICP, EFI The University of
Chicago
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Outline

• Background
• Expectations
• Old Data
• New Data
• Outlook

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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays
• Neutrinos

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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays
• Neutrinos

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Cosmic RaySpectrum
E-2.7

• 1912 discovered by Victor Hess
• Energy range
• 109 eV to gt 1020 eV
• 1938 Pierre Auger
• discovered
• Extensive Air Showers (EAS)

32 orders of magnitude
E-3.1
Ankle (1 particle /km2 yr)
Fixed target (p-A)
Tevatron (p-p)
RHIC (p-p)
HERA (?-p)
LHC (C-C)
LHC (p-p)
12 orders of magnitude
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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays
• Neutrinos

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Cosmic Ray Spectrum

• dN/dE E-2.7 to E-3

X E2.5 ?
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KASCADEComposition at Knee
Large Uncertainties in Monte-Carlo
Simulated Hadronic Interactions - help from
Terrestrial Accelerator Experiments
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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays
• Neutrinos

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CR arrival directions

• Isotropic!

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Photons have zero charge ? travel in
geodesics (straightest lines) point back to source
Galaxies have Magnetic Fields
?

• Cosmic Rays are charged
• (protons nuclei)
• deflected by Magnetic Fields
• do not point back to source

p
B
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Astronomy at Energies above 1019 - 1020 eV
RL1.1 Mpc E21 ?G/B
Dolag et al. 04
Pointing to sources should become feasible at
UHEs!
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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays - yes! Gal CRs
• Neutrinos

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Sources Hidden by Magnetic Fields

• Galactic Cosmic Ray Origin?

Fermi Acceleration in Supernova Shocks? up to
1015 eV - 1017 eV
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HESS - smoking guns in TeV ?s ?
Galactic Centre - 11 ?
RX J1713 - 20 ?
Chandra Radio
Hinton, WatsonFest, Leeds
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Galactic Plane survey from HESS
8 NEW TeV gamma-ray sources some extended
Serendipity 2 completely unknown sources
discovered Survey at 10 Crab Significances
5-gt15? (Science 3/25/2005)
The dawn of TeV Astronomy
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Cosmic Rays Observables

• SPECTRUM
• COMPOSITION
• ANISOTROPIES in Sky
• MULTIPARTICLE INFO
• TeV gamma rays
• Neutrinos

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• Extragalactic
• Protons

Extragalactic Mixed Composition
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UHECRs

• Ultra High Energy Cosmic Rays
• 1018 eV ( EeV) to gt 1020 eV
• Highest energy particles ever observed
• Hadron-like - protons /or heavier nuclei
• Observed through airshowers
• Origin Unknown - Astrophysical /or Physical
  Puzzle
• Anisotropies expected 1019 eV and 1020 eV
• Power law spectrum features expected
• UHECRs ( CMB) generate UHE neutrinos
• UHECRs UHE?s useful to test
• Particle Physics Interactions Relativity

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1905 Einsteins Miraculous Year

• For a protons of
• 1020 eV,
• the age of the Universe
• is less than 2 months!

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Expectations

• Determine their ORIGIN
• Highest energy accelerators in Universe
• Super Massive Black Holes?
• Relics of the Early Universe?
• Determine Spectral Features
• Determine Composition
• Observe Anisotropies in the sky distribution

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Expectations

• Determine their ORIGIN
• Highest energy accelerators in Universe
• Super Massive Black Holes?
• Relics of the Early Universe?
• Determine Spectral Features
• Determine Composition
• Observe Anisotropies in the sky distribution

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High Energy Proton sees Cosmic Microwave
Background as High Energy Gamma Rays!
WMAP
p?cmb? ? ? p ?0 ? n ?
Proton Horizon
GZK Cutoff
Greisen 66, Zatsepin Kuzmin 66
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Extragalactic UHE Protons Propagation
Photo Pion production off cosmic microwave
background (CMB) p?cmb? ? ?p/n?

(Cronin 04)
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Energy losses for protons
Berezinsky et al. 03
redshift
pair
GZK
modification factor Jobs (E,z) ?(E,z) x
Jinjec(E)
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Expectations

• Determine their ORIGIN
• Highest energy accelerators in Universe
• Super Massive Black Holes?
• Relics of the Early Universe?
• Determine Spectral Features
• Determine Composition
• Observe Anisotropies in the sky distribution
• Need to reach gt 104 - 105 km2 sr yr
• Present experiments 103 km2 sr yr

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Old Data

• Challenge to reach gt 104 - 105 km2 sr yr
• Present experiments 103 km2 sr yr
• AGASA (100 km2 array scintillators)
• exposure 1.6 103 km2 sr yr
• HiRes (Binocular Fluorescence Telescopes)
• exposure 2 103 km2 sr yr
• Controversy over spectrum anisotropies

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AGASA Ground Array
High Resolution Flys Eye
100 km2 scintillators muon detectors
2 fluorescence telescopes
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AGASA
High Resolution Flys Eye
Clustering of Events above 4 x 1019 eV
No small scale clustering
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AGASA
High Resolution Flys Eye
Consistent w/ GZK cutoff
No GZK cutoff
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Low Statistics Systematic Errors
AGASA
AGASA-15
HiRes 15
no GZK _at_ 2.5 ?
DDM, Blasi, Olinto 2003, AP in press
HiRes
1.5 ?
Emax1021.5 eV
DDeMarco, Blasi, AO 03
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Systematic off-set
Thanks to D. Bergman
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Pierre Auger Project

• 2 Giant Ground Array (30 x AGASA) with
  Fluorescence Detectors
• HYBRID DETECTOR - use both techniques

HIGH QUALITY
LARGE QUANTITY
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New Data

• Challenge to reach gt 104 - 105 km2 sr yr
• Present experiments 103 km2 sr yr
• AGASA (100 km2 array scintillators)
• exposure 1.6 103 km2 sr yr
• HiRes (Binocular Fluorescence Telescopes)
• exposure 2 103 km2 sr yr
• PIERRE AUGER Observatory (South)
• 3,000 km2 array 4 Fluorescence Telescopes
• Aperture 6,600 km2 sr - reach gt 104 in 2 years

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The Observatory Plan
Surface Array 1600 detector stations 1.5 km
spacing 3000 km2
Fluorescence Detectors 4 Telescope enclosures 6
Telescopes per enclosure 24 Telescopes total
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Auger South
Construction
gt 1000 surface detector stations deployed (900
with electronics and sending triggers) Three
fluorescence buildings complete each with 6
telescopes
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Pierre Auger Observatory
2 Giant AirShower Arrays South Argentina
Funded, North Not Yet 1600 particle detectors
over 3000 km2 4 Fluorescence Detectors to
Measure Direction, Energy, Composition of
60 events/yr E gt 1020eVand 6000 events/yr E gt
1019eV gt 250 scientists from 16 countries
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tanks aligned seen from Los Leones (test your
eyes)
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tanks aligned seen from Los Leones (zoomed)
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Auger Water Cherenkov Detector
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Example Event 1 A moderate angle event
762238Zenith angle 48º, Energy 70 EeV
Flash ADC traces
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Example Event 2 A high zenith angle event -
787469Zenith angle 60º, Energy 86 EeV

Lateral density distribution
Flash ADC traces
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view of Los Leones Fluorescence
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corrector lens (aperture x2)
440 PMT camera 1.5 per pixel
segmented spherical mirror
aperture box shutter filter UV pass safety curtain
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Atmospheric Monitoring Fluorescence Detector
Calibration
Absolute Calibration
Atmospheric Monitoring

• Central Laser Facility (laser optically linked to
  adjacent surface detector tank)
• Atmospheric monitoring
• Calibration checks
• Timing checks

Radiosondes for atm profile
Drum for uniform illumination of each
fluorescence camera
Lidar at each fluorescence eye for atmospheric
profiling - shooting the shower
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FD Stereo Event

• Threshold trigger on
• individual pixels -
• tracks 1 Hz trigger rate per 6 cameras
• Multi-camera events merged within 2 sec
• Geometry recon in 5 sec, passed to central data
  acquisition system
• Induces SD readout of tanks within range.
• Obtain Hybrid Events with both longitudinal and
  transverse shower information.

A Stereo Event
100ns time bin
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Example Event 3 A hybrid event 1021302Zenith
angle 30º, Energy 10 EeV
Fitted Electromagnetic Shower
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Example Event 3 A hybrid event 1021302Zenith
angle 30º, Energy 10 EeV
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First Auger Data Set

• Collection period
• 1 Jan 2004 to 5 June 2005
• Zenith angles - 0 - 60º
• Current rate - 18,000 / month
• Total - 150,000
• Surface array events
• (after quality cuts)
• Total Exposure 1750 km2 sr yr
• ( 1.07 AGASA)

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Hybrid Events

• Reconstructed
• 1,800/month
• Total 10,000
• Mostly at low energies near eyes
• 2000 (gt1 EeV)

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Sky Map of Data set
Auger latitude -36. Always looking towards
South. Limited coverage in Northern region.
Galactic coordinates
Mainly measure properties of the Southern sky
flux!
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Previous Observations of the Galactic Center
AGASA

• AGASA -
• 22 excess at 4.5
• 20 degree window
• near the GC with E1-2.5EeV.
• SUGAR -
• a 2.9s excess with
• 5.5 degree window
• near the GC with E0.8-3.2EeV.

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Auger No excess seen in either region
Our coverage map by shuffling event zenith, day,
hour
Events smoothed with true resolution, Energy
0.8-3.2 EeV
AGASA
SUGAR
Significance of excess or deficit
Smoothed at SUGAR scale, SUGAR energy window
Smoothed at AGASA scale, AGASA energy window
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Search for localized excesses

• Predefined search parameters
• E1-5 EeV, or Egt5 EeV
• Angular scale5 degrees, or 15 degrees (tophat)
• Uses Monte Carlo energy converter instead of CIC
  (for now)

Sky coverage map
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Data is consistent with isotropy
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The Auger Model-Independent Spectrum Approach
Use the strengths from each technique FD(Hybrid)
energy, SD statistics, SD exposure.

• SD data ? ground parameter S(1000) SD signal at
  1000m
• Determine the S(1000)? Energy Zenith Angle
  conversion
• Zenith Angle dependence uses CIC SD and Hybrid
  data
• FD energy scale Normalization via Hybrids
• SD exposure ? measured spectrum.

Each step is empirically determined!
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Flux attenuation in the atmosphereis ? dependent
q 0
q 60
870 g/cm2 11 lI
Earth
The slant depth is 870g/cm2 sec(q)
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First Auger South Energy Spectrum

• dN/d(lnE) EdN/dE
• Errors on points are Statistical only
• Systematic errors are estimated at two energy
  regions
• Energy measurement (horizontal)
• Exposure determination (vertical)

DE/E50
DE/E30
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Comparison with HiRes1, AGASA
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Systematic Errors in the FD (Hybrid) Energy
Normalization
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Comparison with HiRes1, AGASA
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Comparison with HiRes1, AGASA-25
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Two Techniques, Two Spectra
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Muons on the Side
What is the problem? Incorrect Model of
Detector? Incorrect Model of Showers? Heavy
Primaries? New Physics?
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Terrestrial Accelerators Help

• Inclusive Fluxes at Low Energy - atmospheric
  neutrinos
• Brookhaven E910 CERN HARP, NA49 FNAL MIPP
  (E907)
• Extensive Air Showers - pseudorapidity, leading
  particle
• Muon content
• CERN TOTEM, LHCf
• Fluorescence Yield Experiments
• Argonne AIRFLY, SLAC Flash

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Auger (S) x AGASA

DeMarco, Blasi, A.O. 03
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Our Highest Energy Event EFD2 1020eVLanded just
outside the array, so not used in spectrum!
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Blind Watchers

• TO DO list
• Plausible Sources
• - Shock or ? Acceleration Models
• - Spectrum Composition
• - Critical Exposure for Anisotropies
• Monte Carlo vs. Fluorescence CIC - New Physics?
• - Fluorescence Yield
• - MC Hadronic Models vs. Accelerator Phys
  (Forward)
• Design Pierre Auger North - largest exposure for
  

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TowardsAuger North
Auger South (3 yr)
Auger South North
DeMarco, Blasi, AO03
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North ? South
Auger-S gt60o
Auger-N gt60o
Cronin, astro-ph/0402487
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Auger North Colorado site
22,000 km2
Lamar
3,800 km2
Springfield
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Cosmic Rays Observables

• SPECTRUM - great improvement over the next few
  years (Auger S)
• COMPOSITION - challenging but doable
• (Auger S)
• ANISOTROPIES in Sky
• - need bigger observatories (Auger SN)
• MULTIPARTICLE INFO
• TeV gamma rays - yes! Gal CRs Neutrinos - yet
  to come

?
??
100 th Birthday Celebration
?
??
?
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Pierre Auger ProjectSouth North
to discover Ultra-High Energy Cosmic Ray
Sources and Begin
Charged Particle Astronomy
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Chicago
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SD fitting function determined from the data

• LDF (Lateral Distribution Function)
• Distribution of signals versus the core distance
  r (transverse distance of detector to the shower
  axis)

Use a LDF r -b
Auger data 1.2lt sec q lt1.4
sb 10
Measured b(E,q) directly from the data.
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The SD-measured q dependence(Constant Intensity
Cut method)

• Shape is scanned in q
• using bins of Dsin2(q)0.1
• Normalize at the median
• zenith angle of 38 deg.
• Assume CIC(q) is independent of energy.

Use intensity cut corresponding to Egt 3 1018eV
Note bins are correlated!