Results from HiRes and Observation of the GZK Suppression Kai Martens High Energy Astrophysics Institute Department of Physics, University of Utah for the HiRes Collaboration HR1 HR2

August 7, 2007Kai Martens, University of ISMD2 Outline: - Short Introduction to Cosmic Rays - The HiRes Experiment - Monocular Observation: - Going to Extremes - Evidence for GZK Suppression - Stereo Observation: - Checks and Balances - HiRes Composition Measurement - Interpretation: - Ankle, Cutoff, and Cosmogenic Neutrinos - HiRes Neutrino Limits - In Search of the Sources: - Anisotropy - Correlations - Conclusions

August 7, 2007Kai Martens, University of ISMD3 Cosmic Rays GeVTeVPeVEeV (m 2 sr s GeV) km 2 y / Power laws for Flux: J~E  <3 PeV:  =2.7 ~3 PeV: Knee >3 PeV:  =3.0 Swordy Plot: knee ankle

August 7, 2007Kai Martens, University of ISMD4 Air Shower Dimensions Fluorescence Detector: longitudinal profile throughout atmosphere Ground Array: transverse profile at ground level Cosmic Ray showers - start at ~ 15 km above ground - span a couple of km across - hundreds of billions of particles thick water tanks  thin scintillators eV (e/m +  ) (e/m only)

August 7, 2007Kai Martens, University of ISMD5 The HiRes Experiment: 12.6 km apart HR2: 12/ mirrors 3  -31  elevation FADC (100ns) Dugway Proving Grounds HR1: 5/ mirrors 3  -17  elevation Sample&Hold Delta HiRes on DPG:

August 7, 2007Kai Martens, University of ISMD6 HiRes Optics: Mirror surface 5.1 m 2 Field of view: 16  x 14  Camera: 16 x 16 PMT each sees 1 o x 1 o in sky SUN: ½ o UV filter !!! (protecting PMTs) low resolution high speed

August 7, 2007Kai Martens, University of ISMD7 HiRes: Stereo!!! July 11, 1999; Energy: 19 EeV Light Propagation: Atmosphere HR1 HR2 HR1 Dugway Proving Ground

August 7, 2007Kai Martens, University of ISMD8 The Collaboration: S. BenZvi, J. Boyer, B. Connolly, C.B. Finley, B. Knapp, E.J. Mannel, A. O’Neill, M. Seman, S. Westerhoff Columbia University J.F. Amman, M.D. Cooper, C.M. Hoffman, M.H. Holzscheiter, C.A. Painter, J.S. Sarracino, G. Sinnis, T.N. Thompson, D. Tupa Los Alamos National Laboratory J. Belz, M. Kirn University of Montana J.A.J. Matthews, M. Roberts University of New Mexico D.R. Bergman, G. Hughes, D. Ivanov, L. Perera, S.R. Schnetzer, L. Scott, S. Stratton, G.B. Thomson, A. Zech Rutgers University N. Manago, M. Sasaki University of Tokyo R.U. Abbasi, T. Abu-Zayyad, G. Archbold, K. Belov, A. Blake, O. Brusova, Z. Cao, W. Deng, W. Hanlon, P. Huentemeyer, C.C.H. Jui, E.C. Loh, K. Martens, J.N. Matthews, D. Rodriguez, K. Reil, J. Smith, P. Sokolsky, R.W. Springer, B.T. Stokes, S.B. Thomas, L. Wiencke University of Utah Z. Cao, B. Zhang, Y. Zhang, Y. Yang IHEP Bejing

August 7, 2007Kai Martens, University of ISMD9 Challenge: (Mono) Reconstruction angle along horizon  angle above horizon  In-plane Angle (deg) Time (100 ns) angle in plane  Time to common stop  amount of matter (air) traversed  Photoelectrons at detector  light curve + atmosphere = energy Reconstruction steps: 1. shower detector plane 2. Shower axis (full geometry) 3. fluorescence light curve (FADC !!!)

August 7, 2007Kai Martens, University of ISMD10 HiRes Monocular Spectra flux x E 3 HR1: longer exposure  high energy HR2: larger elevation coverage  low energy energy scale uncertainties: - missing energy 5% - energy loss rate10% - fluorescence yield 6% - atmospheric conditions 4% - photometric calibration10%  total (energy):17%   flux uncertainty:30%  =2.8) data: HR1: 5/97-6/05 HR2: 12/99-8/04

August 7, 2007Kai Martens, University of ISMD11 HR1: Aperture Verification - Data vs. MC

August 7, 2007Kai Martens, University of ISMD12 HR2: Aperture Verification - Data vs. MC

August 7, 2007Kai Martens, University of ISMD13 GZK Suppression: ?  !! Old plots: AGASA AGASA (E–20%) avoid double counting: remove HR1 events that also are in the HR2 data set Broken power-law fits: a.) one vs. two breakpoints:  2 reduced by 23.4  4.5  b.) compare measured data to red line extrapolation: expect: 39.9 observe: 13  4.8  (P=7x10 -7 ) Quacks like duck, don’t it?

August 7, 2007Kai Martens, University of ISMD14 Stereo Observation full stereo analysis ongoing; shown: geometry from HR1/HR2plane intersect, light curve from HR2 data only: stereo advantages: geometry constraint (!!!), light balance check on atmosphere energy balance: X max resolution: 30g/mc 2

August 7, 2007Kai Martens, University of ISMD15 Composition from Stereo Data X max distributions: data vs. proton data vs. iron X max [g/cm 2 ] 1820 log 10 (E/eV) Fe + p  |  (mostly) p data: HR prototype HiRes stereo data: ~ 80% p MC: p MC: Fe galactic extra-galactic

August 7, 2007Kai Martens, University of ISMD16 Interpretation of HiRes monocular CR: Doug Bergman, Rutgers (following Berezinsky) Fit interprets spectrum in terms of extragalactic protons that traveled from cosmological sources changed interpretation of ankle: galactic/extragalactic transition: composition change vs. slope change p+    (1232)   +N      +     e  + e +  composition change slope change p+   p+e + +e -  redshift energy  flux  propagation: protons only

August 7, 2007Kai Martens, University of ISMD17 HiRes Composition Guided Fits  flux source model: all sources inject with E    = 2.42 uniform with redshift evolution (1+z) m  m = 2.46 future: astronomy inspired redshift evolution composition as measured !

August 7, 2007Kai Martens, University of ISMD18 The HiRes Neutrino Limits: 90% CL, uncertainty MC statistics only MC injection: E -2 spectrum e limits (no topography): – : 3820 ± – : 3260 ± – : 4250 ±100 event distinguishing features: - horizontal !!! - close to ground target mass:rock detector volume:air  e  LPM     -lepton  limits: – : – : – : fluxes as derived from HR spectrum fit

August 7, 2007Kai Martens, University of ISMD19 MC: Topology at Work  interaction points for  decaying above ground: Cedar Mtns Deep Creek Rng Stansbury MtnsOquirrh Mtns Fish Springs Rng Thomas Rng Sheeprock Mtns  zenith angle in HR system:

August 7, 2007Kai Martens, University of ISMD20 Anisotropy and Clustering Sky Map: HR2 Sky Map:  non-uniform exposure… use MC & on-time database to estimate uniform exposure Point Sources: AGASA for E > 40 EeV: 5 doublets, 1 triplet HiRes stereo +AGASA: 28% of MC > triplet HiRes: E > 30 EeV:  triplet + 1 Looking for Accelerators: Looking for Accelerators: BL lac Tinyakov, Tkachev, Gorbunov analysis: Vernon 9 th, m<18, AGASA+Yakutsk: E>48 (24) EeV  P=10 -4 Vernon 10 th, BL criteria differ, HiRes: E>10 EeV  P=10 -3 HiRes analysis (all events): 0.02%  the jury is still out: more data Findings: - no global dipole - deficit at Galactic Anticenter??? (3.4  )

August 7, 2007Kai Martens, University of ISMD21 Fixed Target 3  eV HiRes 2007 HiRes: mean energy: ~ eV “protons” selected X max  Data:

August 7, 2007Kai Martens, University of ISMD22 Now Commissioning: Telescope Array T A 3 x 120 deg fluorescence telescopes MCCRC Delta, UT 2h from SLC 512 x 3m 2 scintillator array

August 7, 2007Kai Martens, University of ISMD23 Conclusions HiRes has finished taking data HiRes has changed the cosmic ray (CR) landscape: - extragalactic CR mostly protons - GZK suppression present in data   + resonance - ankle likely e + e -, not transition to extragalactic…  spectral features important  TALE HiRes finds no significant UHE-CR anisotropies HiRes finds no significant UHE-CR clustering Correlations with astrophysical sources: jury still out Ultra High Energy (UHE) CR research is alive in Utah:  Come and join our efforts for TA/TALE

August 7, 2007Kai Martens, University of ISMD24 HiRes & Auger Limits