# Presentation: 559637

## DOE Annual Program Review

Pierre Auger Project (E881)
Peter O. Mazur

**Pierre Auger Project (E881)**
**Peter O. Mazur**

## 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**

- Pierre Auger Project

- September 26, 2007

## 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

- September 26, 2007

## The Pierre Auger Project

**A new cosmic ray observatory to study the highest energy cosmic rays, >10****18.5****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.**

- Pierre Auger Project

- September 26, 2007

## Times at angles,Χ, are key to finding Rp

**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**

- Pierre Auger Project

- September 26, 2007

## Time, t

**Time, t**

- Χ°

**R****p ****km**

- Pierre Auger Project

- September 26, 2007

## 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**

- Pierre Auger Project

- September 26, 2007

## Slide 8

- Pierre Auger Project

- September 26, 2007

- Pierre Auger Project

- September 26, 2007

## 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**

- Pierre Auger Project

- September 26, 2007

## 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

- September 26, 2007

## 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

- September 26, 2007

## 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

- September 26, 2007

## Fourfold Hybrid Event, 1019eV

- Pierre Auger Project

- September 26, 2007

## Number of Events

- Pierre Auger Project

- September 26, 2007

## Disagreement in Xmax Distribution

**Large number of events allows good control **
**and understanding of systematics**

**111   69      25       12**

**426**

**326**

**Disagreement in X****max ****Distribution**

- Pierre Auger Project

- September 26, 2007

## Elongation Rate over Two Decades in Energy

**Fluctuations in X****max ****to be exploited**

**Elongation Rate over Two Decades in Energy**

- Pierre Auger Project

- September 26, 2007

## 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

- September 26, 2007

## The Cosmic Ray Spectrum

- Pierre Auger Project

- September 26, 2007

## Energy spectrum from SD < 60°

- Energy spectrum from SD < 60°

**Calibration unc. 18%**

**FD syst. unc. 22%**

**5165 km****2**** sr yr  ~ 0.8 full Auger year**

**                      ****Exp         Obs**
**>10****19.6****     132 +/- 9         51 **
**> 10****20****        30 +/- 2.5        2**

**Slope = -2.62 ****± 0.03**

- Pierre Auger Project

- September 26, 2007

## Spectral Slope Changes with Energy

**Spectral Slope Changes with Energy**

- Pierre Auger Project

- September 26, 2007

## Spectral Slope Disagreements

- Pierre Auger Project

- September 26, 2007

## What Does It All Mean?

**          ****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?**

- Pierre Auger Project

- September 26, 2007

## 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

- September 26, 2007

## 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

- September 26, 2007