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

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DOE Annual Program Review

Pierre Auger Project (E881)

Peter O. Mazur

September 26, 2007 2

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Pierre Auger Project

The Pierre Auger Collaboration

Czech Republic France Germany ItalyNetherlandsPoland PortugalSlovenia Spain United Kingdom

ArgentinaAustraliaBrasilBolivia*MexicoUSAVietnam*

*Associate Countries

~300 PhD scientists from ~70 Institutions and 17

countriesAim: To measure properties of UHECR with unprecedented

statistics and precision – necessary even if no disagreement


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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


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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.


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The essence of the hybrid approach

Precise shower geometry fromdegeneracy given by SD timing

Essential step towards high quality energy and Xmax resolution

Times at angles,Χ, are key to finding Rp


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Time, t

Χ°

Rp km


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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


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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


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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.


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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


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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 publicationsC. Newman-Holmes – CFO; Studies of operational

stabilityL. Voyvodic (retired) – Composition/proton cross-

section studies, Auger internal publicationsP. Lebrun– Studies of operational stability.

Maintenance of Auger data mirror and database. P. Kasper-Recently joinedM. Kaducak (P.E.)-Project Engineer


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Fourfold Hybrid Event, 1019eV


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Number of Events


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Large number of events allows good control and understanding of systematics

111 69 25 12

426

326

Disagreement in Xmax Distribution


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Fluctuations in Xmax to be exploited

Elongation Rate over Two Decades in Energy


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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 confirmedBUT, a ‘prescription’ is currently being tested


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The Cosmic Ray Spectrum


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Energy spectrum from SD < 60°

Calibration unc. 18%FD syst. unc. 22%

5165 km2 sr yr ~ 0.8 full Auger year

Exp Obs>1019.6 132 +/- 9 51

> 1020 30 +/- 2.5 2

Slope = -2.62 ± 0.03


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Spectral Slope Changes with Energy


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Spectral Slope Disagreements


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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?


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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


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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

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

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