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

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

2. 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 The Pierre Auger Collaboration Aim: To measure properties of UHECR with unprecedented statistics and precision – necessary even if no disagreement Pierre Auger Project

3. Participating US Institutions • UCLA Michigan Tech • Case Western Minnesota • Chicago Nebraska • Colorado New Mexico • Colorado State Northeastern • Columbia Ohio State • Fermilab (and ANL) Utah • Louisiana State • Plus 8 Associate Member Institutions Pierre Auger Project

4. The Pierre Auger Project • A new cosmic ray observatory to study the highest energy cosmic rays, >1018.5eV. • Two large air shower detectors: • 3000 km2 nearing completion in Argentina • Larger, in planning, for Colorado • The observatory is a hybrid: both surface detectors and fluorescence detectors. Pierre Auger Project

5. The essence of the hybrid approach Preciseshower geometryfrom degeneracy given by SD timing Essential step towards high quality energy and Xmax resolution Times at angles,Χ, are key to finding Rp Pierre Auger Project

6. Time, t Rp km Χ° Pierre Auger Project

7. 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 The Hybrid Era Pierre Auger Project

8. Pierre Auger Project

9. Pierre Auger Project

10. 1507 deployed 1449 filled 1413 taking data 9/9/07 ~ 88% All 4 fluorescence buildings complete, each with 6 telescopes AIM: 1600 tanks The Southern Observatory Pierre Auger Project

11. 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. Pierre Auger Project

12. 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 Pierre Auger Project

13. 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 Pierre Auger Project

14. Fourfold Hybrid Event, 1019eV Pierre Auger Project

15. Number of Events Pierre Auger Project

16. Disagreement in Xmax Distribution 326 111 69 25 12 426 Large number of events allows good control and understanding of systematics Pierre Auger Project

17. Elongation Rate over Two Decades in Energy Fluctuations in Xmax to be exploited Pierre Auger Project

18. 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 Pierre Auger Project

19. The Cosmic Ray Spectrum Pierre Auger Project

20. Energy spectrum from SD < 60° Slope = -2.62 ± 0.03 Exp Obs >1019.6 132 +/- 9 51 > 1020 30 +/- 2.5 2 Calibration unc. 18% FD syst. unc. 22% 5165 km2 sr yr ~ 0.8 full Auger year Pierre Auger Project

21. Spectral Slope Changes with Energy Pierre Auger Project

22. Spectral Slope Disagreements Pierre Auger Project

23. What Does It All Mean? 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 Pierre Auger Project

24. 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 Pierre Auger Project

25. 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 1017 eV • Submit Auger North proposal within a year Pierre Auger Project