The Pierre Auger Project. Angela Olinto University of Chicago

Transcription

1 The Pierre Auger Project Angela Olinto University of Chicago

2 Cosmic Rays 1912 discovered by Victor Hess (after work of Wilson & others) Energy range: 10 9 ev to = ev direct detection up to ev & indirect det. above ev via: Extensive Air Showers (EAS) discovered by Pierre Auger, 1938 Spectrum: featureless J ~ E -2.7, 10 8 ev < E < ev THE KNEE J ~ E -3, ev < E < ev Detectors: Ground Arrays scintillator /water-cerenkov detectors (> 8km 2 ): Volcano Ranch(US), Haverah Park(UK), SUGAR (Au), Yakutsk (Ru), AGASA(Jp) 170 km 2 Fluorescence Detectors Fly s Eye, High Resolution F.E E. Fermi E < ev SN shock acceleration

3 Cosmic Ray Spectrum Compilation by S. Swordy

4 AGASA

5 Surprise! Events with energies = ev EXIST!!!! Fly s Eye record holder (10/91): ev AGASA (90-00): 8 events above ev & 728 events above ev HiRes Fly seye (99-00): 7? events > ev Haverah Park (1987): 4 events > ev Volcano Ranch (1962): 1 event > ev NO GZK cutoff!!! (Greisen-Zatsepin-Kuzmin 66) photo-pion production off CMB limits source of UHE protons (E > ev) distances to less then ~ Mpc Nuclei, γ, & grains don t do any better Fe diffuse infrared background γ radio background e+e- production grains UV background No Counterparts: No Cosmic Ray Astronomy Yet!!! above ev maybe at ev

6 Highest-Energy Cosmic Rays The photopion production cutoff ~ 7 x10 19 ev is not observed! No GZK Cutoff!!! Consistent with Haverah Park & Fly s Eye experiments

7 Extragalactic UHECRs Protons, nuclei and gamma rays lose energy in intergalactic space Proton energy vs. distance (J. Cronin) Energy loss on Cosmic Microwave Background

8 The UHECR Challenge Energy: = ev Flux: = 1 particle/km 2 /century Spectrum: J ~ E -3, ev < E < ev, J ~ E -2 to E -1, E > ev, NEW COMPONENT?? UHECRs vs. EHECRs or SCRs? Cosmography: Arrival Directions Isotropic don t see: Galaxy, Local Group, Local SuperCluster In future could see: Halo of Galaxy(???), AGNs? But above ev only 7 (AGASA) - 20 events! Composition: µ content on the ground and depth of shower Max FE event: Proton or Fe not γ?? AGASA: trend is unclear same as lower Energy Cluster of Events: (Takeda et al 99) Doublets & Triplets = ev (2.5 o ) (1% chance) Indicates Long Lived Sources or Clumpiness or Focusing

9 FACING THE CHALLENGE NO Model Fits All the Data (without some Miracle B!) Outer Space : Use Known Physics and Astrophysics Discard some piece of the Data ZEVATRONs Bottom-Up Inner Space: Let Your imagination Free Top-Down why walk up if we can take the ski-lift?

10 Bottom-Up ZEVATRONs = Astrophysical Accelerators reach ZeV s Energy: = ev is the 1st challenge (If 1 TeV is hard imagine 10 9 TeV!!) Propagation: the 2 nd challenge B igm (determines the spectrum and arrival direction) Acceleration = Macroscopic motions transferred to particles a la Fermi Hillas plot: require particles to be contained, ie, Gyroradius < size of Accelerator Not many objects left: Neutron Stars AGNs Radio Lobes Clusters Colliding Galaxies/Clusters Gamma Ray Bursts

11 Neutron Stars: If to close to the polar cap - High Losses but Outside the light cylinder... Young Neutron Star Winds (Venkatesan, Miller, & A.O. 97) (Blasi, Epstein, A.O. 00, A.O., Epstein, Blasi 99) Neutron stars are born w/ large B & W slow down by B & Gmn radiation Iron nuclei accelerated from light cylinder by relativistic MHD winds (Γ ) reach E max ev Column density of SNR envelope needs to below enough for the Iron nuclei to escape while star still spins fast This Zevatron is a Cyclotron B r -1, r > R lc Particle contained in accelerating region Tests: Spectrum FLAT!! N(E) E -1 Composition: Iron Location: Galactic plane for the highest energies

12 AGNs: Central Regions High energy g observed - E max ev but too many losses (Norman,Melrose, Achterberg 95) GZK plus Cosmography hurt. Dead Quasars maybe but GZK cut! (Bolt & Ghosh 99) Radio Lobes E max = ev (Rachen & Bierman 93) E max = ev (Bierman 00) But, in general they are Too far!! Except for M87, Need very specific B Gal & B igm

13 M87

14 Clusters Cluster Accretion Shocks E max ev (Kang, Ryu, & Bierman 95) Galactic Winds E max ev (Jokopii & Morfill 85) Even if energy is close, they don t get out (Blasi 99) Gamma Ray Bursts Transient Relativistic Shocks Similar p & g fluxes (Waxman 95) Relativistic shocks: not enough G (Achterberg 99) flux too low (Stecker 99) needs B igm = G E 20 /d 30 /l 1 0.5

15 Half & Half Aproach: New Particles from Astrophysical Zevatrons For Ex: Uhecrons - Heavy-quark composites (Chung, Farrar, & Kolb 98) FE shower development says: Not above 50 GeV (Albuquerque, Farrar, & Kolb 98) Monopoles No also: (FE shower development) Unless (Weiler & Kephart 96) (Wick, Kephart, Weiler & Bierman 00) UHE Neutrinos scatter off n background: Z-pole (Weiler 82) Needs Very High Energy (High Flux) Neutrino Source Tests: No Clustering!!! Gamma primaries

16 Top-Down Physics Beyond the SM Energy >> ev is Easy! (Usually start at ev or higher!!) Flux is the challenge!! (determined by typical separation scales H 0-1 ) & Composition!! Topological Defects generated in the early Universe through the Kibble Mechanism as symmetries are broken. (Hill 83, Hill, Schramm, & Walker 87, Bhattacharjee, Hill, Schramm 92, Sigl, Bhattacharjee, Schramm 94) Super Conducting Strings (Hill, Schramm &Walker 85) Cosmic Strings (Bhattacharjee & Rana 90) Monopolia (Hill 83, Bhattacharjee & Sigl 95) String Cusps (Brandenberger 87) Monop-String Network (Berezinsky Martin &Vilenkin97) Necklaces (Berezinsky & Vilenkin 97) Vortons (Masperi & Silva 98) Super Heavy Relic particles Metastable (Kuzmin &Rubakov 97; Berezinsky, Kachelriess, &Vilenkin 97) Dark Matter Halo Distribution - small percentage decays today - Cryptons,

17 Early Universe Relics produced after or at the end of inflation, decay today producing X-particles that decay QCD fragmentation spectrum Cosmic Strings & Superconducting Strings are too far apart Flux too low! Monopole-Anti-Monopole: G H x U(1) Too Many Inflate Too Few Fine Tune!!! Monopolonia Orbits decay 99) Monopoles w/ Strings Attached G H x U(1) H x Z N acceleration of monopoles create UHECRs Flux too low! Cosmic Necklaces N=2 above. Distance between beads can be just right : OK! SuperHeavy Relics: live long via Symmetry Protection Plan (Chung, Kolb, & Riotto 98, Kuzmin & Tkachev 98) long lived weakly interacting = CDM M x > GeV (Berezinsky, Blasi, and Vilenkin 98) EGRET constrains g flux at 10 MeV and 100 GeV Constrains UHE g s and e s via secondary lower energy g s (CMB & Radio Background) ) Signatures: Composition: fragmentation lead to g >> proton Spectrum: QCD fragmentation NOT Power law like the Zevatrons! Halo Distribution!! (SHRs & Local TDs)

18 The CHALLENGE is back in Experimental Arena Bottom-Up Signatures: Protons/Nuclei Power Law Spectrum Counterparts (or B) Top-Down Signatures: Photons Non-Power Law Spectrum No Counterparts/ Repeats Halo Distribution

19 International Collaboration 2 Giant AirShower Arrays South Argentina Funded North Utah Not Funded Yet 1600 particle detectors spread over 3000 km Fluorescence Detectors/each Will Measure Direction, Energy, & Composition of ~60 events/year E > ev ~6000 events/year E > ev + Horizontal Showers = UHE Neutrinos!

20 Auger Project Combined Fluorescense & Ground Array detectors

21 Auger Detectors

22 Auger vs. AGASA

23 Engineering Array from satellite

24 Pampa Amarilla Site

25 First Tank - Priscila

26 The Size of Auger

27 Auger Collaboration

28 UHECRs Mystery +... AGASA sees (2000): 8 events E >10 20 ev 728 events E >10 19 ev Auger will see (3yr): ~100 events E >10 20 ev ~10000 events E >10 19 ev

29 + UHE Neutrinos!!!! HORIZONTAL SHOWERS Can Probe: Neutrino Cross Sections Above the Standard Model Tau showers from the Earth or the Andes

30 Fly s Eye saw 0!! But there are GZK n s!! s nn (10 19 ev) = cm 2 Auger can reach ~ s nn SM probe interactions beyond Standard Model s nn (10 19 ev) = s nn SM ~ cm 2 Auger can also detect t decays! n t ( ev) produce t s Andes (50 km) or Ground (upward n t s) n m n t Full mixing GZK n t s!!!

31 EUSO - OWL Airwatch Ni Fluorescence from ABOVE! = 30 x Auger 3000 events/year E > ev!!! UHE Neutrinos!

32 The Pierre Auger Project Engineering Array Starting this Spring!! Full Project On ~ 2003 STAY TUNED!!!!