Future Plansand

Summary

Gordon Thomson

Rutgers University

Outline

• Future Plans– Operations and Maintenance– Upcoming Publications

• Spectrum• Composition• Anisotropy• Other Analysis results

– Physics Projections for Four Years more Data Collection

• Comparison with Other Experiments• Summary

Operations• Threatcon Alpha

– Run HiRes1 remotely.– U.S. citizens run HiRes2

(Foreign citizens?).– Develop HiRes2 remote running.

• Backup network connection.• Improve breakers.• Curtains for east-facing mirrors.

– Aim: one person on base, on call at English Village, both detectors run remotely.

• Return to Threatcon Charlie?– Remote ops at both detectors.– Get more clearances (now four +

LANL, plus others in pipeline).

Maintenance and Calibration

• Fix bad channels and phototubes: a few per mirror at both detectors.

• Reoptimize HV (e.g., HiRes1 M3 too low).

• Resume monthly RXF calibration runs.

• New calibration steps.– Cross calibrate RXF to NIST standard detectors

(first look: agree to ~6%).– 4 km vertical laser (end to end) calibration.– Remeasure mirror reflectivity.

Upcoming Publications• Spectrum

Measurements:– Stereo spectrum.

– HiRes1 mono spectrum long paper.

– HiRes2 mono spectrum (extension to data sets 1-3), and fits to HiRes mono spectra.

– Stereo and mono spectra with hourly atmospheric corrections.

• Stereo composition.

Upcoming Publications (cont’d)

• HiRes1 mono anisotropy: – point source search.– GF analysis.– dipole search

(submitted).– galactic and

supergalactic plane searches.

• Stereo anisotropy:– Point source search.– Consistency of Agasa

cluster results (submitted by C.F. and S.W.).

Other Analyses in Progress• P-Air total cross section (K.B).

– Stereo measurement of Xmax.

– Separates dependence of Xmax on shower development and depth of first interaction.

– Gets shower development from Corsika/QGSJet.

• HiRes2 mono composition measurement.

• HiRes2 mono anisotropy studies.

• Composition and spectrum in selected areas of sky.

Collect Data Thru October, 2007

• Now:– HR1 mono = 47 mo. (thru 3/03) – Stereo = 27 mo. (thru 3/03)– HR2 mono = 17 mo. (thru 9/01)– Composition = 17 mo. (thru 9/01)

• Run Thru October, 2007:– HR1 mono = 102 mo. (x 2.2) – Stereo = 82 mo. (x 3.0)– HR2 mono = 82 mo. (x 4.8)– Composition = 82 mo. (x 4.8)

Mono Spectrum in 2007

Significance of Spectrum Turnover at GZK Threshold

• Test Agasa interpretation that spectrum continues at E-2.8

• Now turnover significance is 4 sigma.

• We reported 3 sigma one year ago.

• In 2007 we expect better than 6 sigma.

• Statistical power is crucial.

Composition in 2007• Stereo: improve statistics by x4.8

• Coming up: HiRes2 mono composition. – Can reach down to ~17.5– Will see the highest energy part of the galactic-

extragalactic transition, all in one experiment.– Will need tight cuts, hence the best statistics is crucial.

Anisotropy near Galactic Center at 1018 eV

• Akeno/Agasa, Sugar, Fly’s Eye each have a small excess

• Akeno/Agasa have 18k events, with 4% excess.

• HiRes2 mono has only data being collected in this energy range:– Energy histogram peaks at

1018 eV– Will have ~12k events in

2007.

• Again statistical power is crucial.

Comparison with Other Experiments: Agasa

• Ends next month.

• Sensitivity < HiRes above 3x1019 eV.

• Spectrum: big difference in methodology.

• Clusters: not confirmed.

• Large scale anisotropy near 1018 eV: – Supported by Fly’s Eye, Sugar

– Will be tested by HiRes.

Pierre Auger South• Water Cerenkov SD

– instantaneous aperture ~ HiRes, – 100% duty cycle; times 8 overall.– threshold ~1019 eV for spectrum determination;

• FD aperture ~ HiRes;– Hybrid threshold ~1018 eV for anisotropy.

• 100 tanks now in place, out of 1600, plus 3 mirrors.• Complete in 2006.• SD is main statistics engine.• FD / hybrid for energy scale determination (excellent

angular resolution).• SD will equal HiRes statistics in 2007.• SD/FD energy scale measurement will take time (~150

events/year above 1019 eV).• FD / hybrid will equal HiRes statistics in 2012.

Telescope Array (TA)

• Scintillator SD about 1/4 the size of Auger, plus FD for hybrid observation. SD threshold at 1019 eV.

• Approximately equal apertures in SD, FD.

• Funded (at ~85% level) for 24x24 scintillation counters, plus two rings of fluorescence detectors.

• 4-6 year project: – 1.7+3.3+3.3+1.7+1+1=$12M

– Four years of construction. Two years of deployment?

• To be built in Millard County, Utah.

Pierre Auger North

• Slated for Millard County, Utah (Lamar, Colorado a possibility).

• Funding unlikely before 2007.

• Baseline design: like Auger South.

• But no decisions made on SD size, FD size.

Summary: Operations

• Detectors are working well.

• Data collection on three-hour nights.

• Operating HiRes1 remotely; two HiRes2 operators at Camel’s Back Ridge.

• Improving phototube calibration (aim: 5%).

• Improving atmospheric analysis.

• On track for 5-year goals as stated in 2002.

Summary: Physics Results• HiRes mono spectra:

– See three spectral features;

– Two positions at CMBR-interaction thresholds;

– Fit spectrum and composition, can find distance to sources.

– Position of the ankle is crucial for astrophysics;

– Must understand the galactic flux to understand the extragalactic flux: composition is important.

• HiRes stereo spectrum: – Modest statistics as yet;

– Will extend energy coverage and statistics;

– Agrees well with mono.

• Stereo composition measurement: – Composition is light from 1018 to 1019.4

– Extends HiRes-MIA result.

Physics Results (cont’d.)• HiRes1 mono anisotropy:

– No evidence for point sources yet;

– No confirmation of Agasa clusters;

– No dipole distributions seen.

• Stereo anisotropy: – Excellent angular resolution;

– No evidence yet for point sources.

The Big Picture

• We are making progress in understanding the UHE cosmic rays:

– HiRes is verifying and extending previous measurements of spectrum and composition, from Fly’s Eye and other experiments.

– We see evidence for the galactic–extragalactic transition.

– We see evidence for interactions between cosmic rays + CMB photons.

– The GZK cutoff seems to be present.

– The position of the ankle is important.

– Cosmic ray astronomy (a.k.a. anisotropy studies) is in its infancy.