Pierre Auger Observatory for UHE Cosmic Rays Gianni Navarra (INFN-University of Torino) for the Pierre Auger Collaboration XXXXth Rencontres de Moriond ElectroWeak Interactions and Unified Theories La Thuile 5-12th March 2005 Science Case: the need for Auger Principles and Advantages of a Hybrid Detector Present Status of the Observatory First preliminary Data Perspectives

Pierre Auger Collaboration Spokesperson: Alan Watson 16 Countries 50 Institutions ~350 Scientists Italy Argentina Czech Republic Australia France Brazil Germany Bolivia * GreeceMexico Poland USA Slovenia Vietnam * Spain United Kingdom * Associate Countries

UHE Cosmic Rays Eo >10 20 eV: 1 part / (km 2 century sr)  10 2 – 10 3 km 2 collecting areas Surface particle detectors

atmospheric fluorescence detectors UHE Cosmic Rays Eo >10 20 eV: 1 part / (km 2 century sr)  10 2 – 10 3 km 2 collecting areas Atmospheric fluorescence detectors

HiRes vs AGASA AGASA HiReS D. Bergmann ~ 30 % Syst. Error Atmospheric fluorescence detectors Surface particle detectors

GZK? pair production energy loss pion production energy loss pion production rate Cosmic ray sources are close by (<100 Mpc) eV 3 Gpc B = 1nG B intergalactic -  ~ degree  Sources !!! Astrophysics?

Relic Particles in Galactic Halo ? M relic = eV; SUSY evolution, n-body decay Composition (p,…Fe  ) + Astronomy (point sources) Sakar & Toldrà, Nucl.Phys.B621: ,2002 Toldrà, astro-ph/ Fundamental Physics ?

Required to solve EHECR-Puzzle: Better understanding of Syst. Errors Better understanding of Syst. Errors Better Resolution in Energy and Direction Better Resolution in Energy and Direction Much more Statistics Much more Statistics  Hybrid Approach: Independent EAS-observation techniques Shower-by-Shower in one Experiment Independent EAS-observation techniques Shower-by-Shower in one Experiment  Much larger Experiment

Atmospheric fluorescence detectors UHE Cosmic Rays with Auger Eo >10 20 eV: 1 part / (km 2 century sr)  10 2 – 10 3 km 2 collecting areas Surface particle detectors Atmospheric fluorescence detectors

70 km Southern Site Pampa Amarilla; Province of Mendoza 3000 km 2, 875 g/cm 2, 1400 m Lat.: 35.5° south Surface Array: 1600 Water Tanks 1.5 km spacing 3000 km 2 Surface Array: 1600 Water Tanks 1.5 km spacing 3000 km 2 Fluorescence Detectors: 4 Sites 6 Telescopes per site (180° x 30°) 24 Telescopes total Fluorescence Detectors: 4 Sites 6 Telescopes per site (180° x 30°) 24 Telescopes total LOMA AMARILLA

View of Los Leones Fluorescence Site

Six Telescopes viewing 30°x30° each

Schmidt corrector ring  2.2 m opt. Filter (MUG-6) UV optical filter (also: provide protection from outside dust) Camera with 440 PMTs (Photonis XP 3062) Schmidt Telescope using 11 m 2 mirrors

Coihueco (fully operational) Lomo Amarilla (in preparation) Morados handed to Collaboration Los Leones (fully operational)

Aligned Water Tanks as seen from Los Leones

Water Tank in the Pampa Solar Panel Electronics enclosure 40 MHz FADC, local triggers, 10 Watts Communication antenna GPS antenna Battery box Plastic tank with 12 tons of water three 9” PMTs

receiving tanks Tank Preparation and Assembly Transportation into field Water deployment installation of electronics Installation Chain

650 Water Tanks (out of 1600) + 12 Telescopes Los Leones Coihueco AGASA > 10 x AGASA Southern Site as of Febr. 2005

Calibration

SD Calibration by Single Muon Triggers Agreement with GEANT4 Simulation up to 10  VEM (Vertical Equivalent Muons). VEM ~ 100 PE /PMT Huge Statistics! Systematic error ~5% VEM Peak SumPMT 1 PMT 2PMT 3 Local EM Shower

SD calibration & monitoring single muons Noise Base-Temperature vs Time Signal-Height vs Time Signal-Height vs Base-Temp Single tank response Huge Statistics! Systematic error ~5% ± 3%

All agreed within 10% for the EA Alternative techniques for cross checks Scattered light from laser beam Calibr. light source flown on balloon FD Calibration Absolute: End to End Calibration A Drum device installed at the aperture uniformly illuminates the camera with light from a calibrated source (1/month) Relative: UV LED + optical fibers (1/night) N Photons at diaphragm  FADC counts Mirror Camera Calibrated light source Diffusely reflective drum Drum from outside telescope building

Atmospheric Monitoring Balloon probes  (T,p)-profiles LIDAR at each FD building Central laser facility (fibre linked to tank)  light attenuation length  Aerosol concentration steerable LIDAR facilities located at each FD eye LIDAR at each eye cloud monitors at each eye central laser facility regular balloon flights

Performance demonstrated by First Preliminary Data

Vertical (  ~35 o ) & Inclined (  ~72 o ) Energy ~ (6-7) eV 35 tanks ~ 13 km 14 km 14 tanks ~ 7 km

Young & Old Shower ‘young’ shower ‘old’ shower density falls by factor ~150 … by factor ~4

Vertical vs Horizontal Showers ‘young’ showers Wide time distribution Strong curvature Steep lateral distribution ‘old’ showers Narrow time distribution Weak curvature Flat lateral distribution Only a neutrino can induce a young horizontal shower ! ~ 0.2 µs

(m) ~1  eV ~10 20 eV Lateral Distribution Function ~ 14 km ~ 8 km A Big One: ~10 20 eV,  ~60° 34 tanks ~60° propagation time of 40 µs

EAS as seen by FD-cameras Only pixels with ≥ 40 pe/100 ns are shown (10 MHz FADC  ≤ 4 g/cm 2 ; 12 bit resol., 15 bit dynamic range) Pixel-size = 1.5° ; light spot: 0.65° (90%) eV events trigger up to ~ 30 km Two-Mirror event EAS as seen by FD-cameras

Energy Reconstruction Integral of Longitudinal Shower Profile  Energy preliminary ~ 4.8 Photons / m / electron (~ 0.5 % of dE/dx)

A Stereo Hybrid;  ~70° Coihueco Fluores. Telescope Los Leones Fluores. Telescope ~8 · eV Lateral Distribution Function ~37 km ~24km ~70° global view …zoom

A stereo hybrid;  ~70° ~37 km ~24km

A stereo hybrid;  ~70° Shower Profile ~7 · eV (SD: ~8 · eV)

The Power of Hybrid Observations y x

y y x  SD times  FD times Mono vs Hybrid: uncertainties of Shower core & angle of incidence Verified by using central laser facility mono hybrid Mono ± 0.55 km Hybrid ± 0.02 km

Some numbers: data taking from Jan SD: number of tanks in operation 650 fully efficient above ~ eV number of events ~ 120,000 reconstructed ( > 3fold, >10 18 eV) ~ 16,500 at present ~ 600 events/day FD:number of sites in operation 2 SD+FD:number of hybrids 1750 ~ 350 “golden”

Preliminary Sky Plot Auger-S >85 o Auger-S >60 o no energy cut applied

Distribution of Nearby Matter Auger-S >60 o Auger-N >60 o Jim Cronin, astro-ph/ Mpc

Two Candidate Sites Utah Colorado “Standard” 3,100 km 2 10,000km 2 15,000km 2 TA (800km 2 ) Auger North (3,100 km 2 ) AUGER NORTH

CONCLUSIONS Auger construction in rapid progress in south Physics data taking since January 2004 Auger construction in rapid progress in south Physics data taking since January 2004 Stable operation, excellent performance Hybrid approach is a great advantage! Neutrino sensitivity First physics results by summer 2005 First physics results by summer 2005 Energy spectrum Sky map Auger North proposal in progress

Pampa Amarilla

Hybrid Reconstruction Quality 68% error bounds given detector is optimized for eV, but good Hybrid reconstruction quality at lower energy E(eV)  dir ( o )  Core (m)  E/E (%)  X max g/cm statistical errors only zenith angles < 60 O

High-Energy Neutrinos in Auger  s expected from distant AGN a/o decay of TDs  eV ≈~ cm 2 (Earth opaque for E  eV)  detection by horizontal EAS  If      Oscillations  advantageous for observation of  induced Showers Tests of many AGN & TD Models in range AGN TD

LDF in Hybrid Events good agreement of SD and FD good agreement of SD and MC LDF for eV Showers (Energy from FD) Data points scaled from SD = 1.2  eV

Neutrino Sensitivities (per site) X. Bertou et. al. Astropart. Phys. 17 (2002) 183 Expected no. per year  Limit (E -2 ) for 5 years  Sensitivity e and  Sensitivity High DIS None

Integrated Sensitivity of Various Experiments

High-Energy Neutrinos in Auger  s expected from distant AGN a/o decay of TDs  eV ≈~ cm 2 (Earth opaque for E  eV)  detection by horizontal EAS  If      Oscillations  advantageous for observation of  induced Showers Neutrino Sensitivity (per flavor)