f DOE Annual Program Review Pierre Auger Project (E881) Peter O. Mazur

f September 26, 20072Pierre Auger Project The Pierre Auger Collaboration Czech Republic France Germany Italy Netherlands Poland Portugal Slovenia Spain United Kingdom Argentina Australia Brasil Bolivia* Mexico USA Vietnam* *Associate Countries ~300 PhD scientists from ~70 Institutions and 17 countries Aim: To measure properties of UHECR with unprecedented statistics and precision – necessary even if no disagreement

f September 26, 20073Pierre Auger Project Participating US Institutions UCLAMichigan Tech Case WesternMinnesota ChicagoNebraska ColoradoNew Mexico Colorado StateNortheastern ColumbiaOhio State Fermilab (and ANL)Utah Louisiana State Plus 8 Associate Member Institutions

f September 26, 20074Pierre Auger Project The Pierre Auger Project A new cosmic ray observatory to study the highest energy cosmic rays, > eV. Two large air shower detectors: –3000 km 2 nearing completion in Argentina –Larger, in planning, for Colorado The observatory is a hybrid: both surface detectors and fluorescence detectors.

f September 26, 20075Pierre Auger Project The essence of the hybrid approach Precise shower geometry from degeneracy given by SD timing Essential step towards high quality energy and X max resolution Times at angles, Χ, are key to finding R p

f September 26, 20076Pierre Auger Project Time, t Χ°Χ° R p km

f September 26, 20077Pierre Auger Project The Hybrid Era Angular Resolution Aperture Energy Hybrid SD-only FD-only mono (stereo – low N) ~ 0.2° ~ 1 - 2° ~ 3 - 5° Flat with energy AND E, A, spectral mass (A) and slope and M model (M) free dependent A and M free A and M A and M free dependent

f September 26, 20078Pierre Auger Project

f September 26, 20079Pierre Auger Project

f September 26, Pierre Auger Project The Southern Observatory 1507 deployed 1449 filled 1413 taking data 9/9/07 ~ 88% All 4 fluorescence buildings complete, each with 6 telescopes AIM: 1600 tanks

f September 26, Pierre Auger Project Fermilab Participation Scientists – 4 Full time + 3 Part Time + 1 Retiree 1 postdoc term just completed (Aaron Chou, left for position at NYU) New postdoc accepted offer last week Staff – 2 full time Activities –Project management –Construction –Commissioning –Data analysis –R&D and planning for Auger North Group size - approximately constant; may grow slightly as Auger North evolves.

f September 26, Pierre Auger Project Fermilab Participation Project Management office is here and Project Management personnel are Fermilab (except new Deputy P.M. for Argentina.) Surface Detector co-Task Leader and Subtask Leader positions. Design and engineering support. R&D for Auger North surface detectors. Analysis and publication activities, with a particularly strong postdoc Aaron Chou. ES&H, QA from Fermilab specialists

f September 26, Pierre Auger Project Fermilab Scientist Participation P. Mantsch – Project manager: funding, distribution of resources, construction, operations C. Hojvat – President, Fundacion Observatorio Pierre Auger Argentina (FOPAA) P. Mazur – Surface detector co-task-leader and subtasks leader H. Glass – Cost & schedule; internal publications C. Newman-Holmes – CFO; Studies of operational stability L. Voyvodic (retired) – Composition/proton cross-section studies, Auger internal publications P. Lebrun– Studies of operational stability. Maintenance of Auger data mirror and database. P. Kasper-Recently joined M. Kaducak (P.E.)-Project Engineer

f September 26, Pierre Auger Project Fourfold Hybrid Event, eV

f September 26, Pierre Auger Project Number of Events

f September 26, Pierre Auger Project Large number of events allows good control and understanding of systematics Disagreement in X max Distribution

f September 26, Pierre Auger Project Fluctuations in X max to be exploited Elongation Rate over Two Decades in Energy

f September 26, Pierre Auger Project ARRIVAL DIRECTION DISTRIBUTION Typical accuracy of reconstruction <1° No significant emission from Galactic Center No broadband signals – e.g. Dipole – at any energy above 1 EeV e.g 1 < E < 3 EeV, Amplitude < 0.7% No clustering of the type claimed by AGASA No signal from BL Lacs as possibly seen by HiRes Summary: Previous reports have not been confirmed BUT, a ‘prescription’ is currently being tested

f September 26, Pierre Auger Project The Cosmic Ray Spectrum

f September 26, Pierre Auger Project Energy spectrum from SD < 60° Calibration unc. 18% FD syst. unc. 22% 5165 km 2 sr yr ~ 0.8 full Auger year Exp Obs > / > / Slope = ± 0.03

f September 26, Pierre Auger Project Spectral Slope Changes with Energy

f September 26, Pierre Auger Project Spectral Slope Disagreements

f September 26, Pierre Auger Project Is the ankle marking a galactic/extra-galactic change? Have we seen the GZK effect? Is it a ‘bump’ from a more local effect? Are the accelerators just ‘tired’? What can we deduce from propagation models? Deducing the MASS is crucial: mixed at highest energy? Certainly not expected – do hadronic models need modification? Larger cross-section and/or more muons? Would help to reconcile AGASA with HiRes and Auger at the highest energies Auger statistics will totally dominate after another year What Does It All Mean?

f September 26, Pierre Auger Project Publications in the last year 36 papers plus highlight talk at ICRC2007 –Spectrum –Test of Hadronic Interaction Models –Composition –Photon Limits –Tau Limits –Arrival Direction Clustering –BL Lacs, Galactic Center –Large Scale Anisotropies Galactic Center studies: Astroparticle Physics Photon upper limit: Astroparticle Physics

f September 26, Pierre Auger Project Future for the Auger Collaboration Complete construction of Auger South in ~ 6 months and provide reliable and extensive experimental data for many years (10-20?) After construction of the Observatory is complete, commence construction of high elevation FD (to 60°), dense SD array plus muon detectors (fully funded) for hybrid work down to eV Submit Auger North proposal within a year