1. Future Plans and Summary Gordon Thomson Rutgers University

2. 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

3. 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).

4. 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.

5. 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.

6. 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.).

7. 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.

8. 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)

9. Mono Spectrum in 2007

10. 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.

11. 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.

12. Anisotropy near Galactic Center at 10 18 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 10 18 eV –Will have ~12k events in 2007. Again statistical power is crucial.

13. Comparison with Other Experiments: Agasa Ends next month. Sensitivity < HiRes above 3x10 19 eV. Spectrum: big difference in methodology. Clusters: not confirmed. Large scale anisotropy near 10 18 eV: –Supported by Fly’s Eye, Sugar –Will be tested by HiRes.

14. Pierre Auger South Water Cerenkov SD –instantaneous aperture ~ HiRes, –100% duty cycle; times 8 overall. –threshold ~10 19 eV for spectrum determination; FD aperture ~ HiRes; –Hybrid threshold ~10 18 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 10 19 eV). FD / hybrid will equal HiRes statistics in 2012.

15. Telescope Array (TA) Scintillator SD about 1/4 the size of Auger, plus FD for hybrid observation. SD threshold at 10 19 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.

16. 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.

17. 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.

18. 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 10 18 to 10 19.4 –Extends HiRes-MIA result.

19. 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.

20. 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.