1 / 30

Pierre Auger Observatory

Pierre Auger Observatory. Outline. Cosmic Rays Pierre Auger Observatory Description/Status Enhancements Future Auger Results Auger @ LIP Detector Simulation Measurements Phenomenology Conclusions. M. Pato, P. Assis, P. Brogueira, P. Abreu , P. Gonçalves, B. Tomé, J. Romão,

jam
Download Presentation

Pierre Auger Observatory

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Pierre Auger Observatory

  2. Outline • Cosmic Rays • Pierre Auger Observatory • Description/Status • Enhancements • Future • Auger Results • Auger @ LIP • Detector Simulation • Measurements • Phenomenology • Conclusions M. Pato, P. Assis, P. Brogueira, P. Abreu , P. Gonçalves, B. Tomé, J. Romão, R. Conceição, M. Pimenta, S. Andringa, E. Santos, M. C. Espírito Santo, J. Dias de Deus, J. G. Milhano

  3. Ultra-High Energy Cosmic Rays • Cosmic rays with E > 1020 eV arrive on Earth at the rate of 1 particle per km2 per century • Their composition and their sources are unknown • Create a shower of particles when they enter the atmosphere • Hadronic • Electromagnetic • Can be detected • Ground Arrays • Fluorescence Detector • Moonless nights

  4. Pierre Auger Observatory • The Auger Observatory is a "hybrid detector," employing two independent methods to detect and study high-energy cosmic rays: • Surface detector (SD) • 3000 km2 in the Pampa Argentina • 1600 pure water tanks • 1.5 km spacing • Flourescence Detector (FD) • 4 “eyes” • 6 telescopes in each viewing 30º x 30º • 4 weather stations (with LIDARs) • 2 Laser Facilities FD SD 20 May 2007 E ~ 1019 eV

  5. Event Reconstruction Surface Detector Fluorescence Detector • Tank hit time gives shower direction • Energy is obtained using Nch( distance to the shower core ) • Evolution in camera gives the shower geometry • Energy is calculated by integrating a universal longitudinal profile

  6. Hybrid Technique • Better reconstruction geometry • Higher Xmax resolution • Better energy reconstruction • Calibration of SD with FD • Reduce systematics • Good correlation between SD and FD SD FD

  7. Auger Enhancements AMIGA HEAT Extend studies to lower energies ~ 1017 eV • Auger Muons and Infill for the Ground Array • Study muon component of showers • Good variable to check hadronic models • – Hexagon (7 x 60 m2) • 2 – Infill array 433m • 3 – Existing tank array 1500m • 4 – Infill array 750m • High Elevation Auger Telescopes • 3 “standard” Auger telescopes tilted to cover 30 - 60° elevation

  8. Future Auger North Auger South Extension • Construction 2009-2012 ? • Total area: 20 000 km2 • About 7 x Auger South extension • 4032 surface detectors • 3 FD eyes • Expansion possibilities for Auger South If a non-compact configuration is acceptable • 60 000 km2 ?? • Many possible Upgrades • Radio Antenna Array • … 1 Linsley = 1 L = 1 km2 sr yr

  9. Auger Results Energy Spectrum Anisotropies Xmax

  10. Energy Spectrum • GZK cut-off • Interaction with CMB photons degrades energy • Ankle • Transition from galactic to extra-galactic sources?

  11. Anisotropies Search for Sources ( E > 57 EeV ) positions of (318 visible+164invisible) AGNs at z < 0.018 (D< 75 MPc) 19 out of 27 events are within 3.1º of an AGN !! ( The probability of having an isotropic distributions is 10-5 )

  12. Evidence for Proton Primary? • Angular aperture • α = 3.1 • Distance • z < 0.018 → D < 75 MPc • Energy • E > 57 EeV Low E High Z High E Low Z The angular aperture suggests that the particle is a proton!

  13. Xmax – Primary Composition • Iron showers develop faster than proton • Slope depends strongly on the interaction models • Auger data indicates heavier composition at high energy!!!!! Particle Physics?!...

  14. LIP @ Auger Particle Physics @ Cosmic Rays Good understand of the detector Geant 4 Simulation of the FD Simulation studies for AMIGA New variables from data 3D Analysis Čerenkov Phenomenological Models

  15. FD Simulation with Geant 4 Going into detail...

  16. Geant 4 Simulation Mirror curvature from database!! • Good overall agreement with official simulation • Small differences with some more realistic settings • Good tool to find systematics!!

  17. New possibilities…

  18. Simulation studies for AMIGA • Muon selection effieciencies of 80 to 90% • About 10% of multihits

  19. 3D Reconstruction Method • Currently for FD the shower is being treated as a 1D object but it’s an 3D object • It is possible to get information about the “width” of the shower taking the arrival time of photons at the detector into account • It uses time as a 3rd dimension Adding Time

  20. 3D Reconstruction Method Longitudinal Profile Lateral Profile Simulation • This method obtains a good agreement with the simulation • Longitudinal Profile • Lateral Profile • Low statistics Ratio Expected / Observed

  21. 3D Reconstruction Method Longitudinal Profile Lateral Profile Experimental Data • 6 Months of data • Longitudinal Profile shows a good agreement • Lateral Profile shows a clear disagreement • Data seems wider • Detector? • Physics?? Ratio Expected / Observed

  22. 3D Simulation • Currently: • Čerenkov and fluorescence photons are produced from longitudinal profiles (1D) • All photons are propagated to the lens and then spread transversally • A 3D Reconstruction needs a 3D Simulation! Auger Simulation and Reconstruction Software (Offline) with some modifications

  23. 3D Simulation Already a first shower… Shower at 4980 m from Los Leones – seen in Eye 1

  24. a Shower axis c0 FD Čerenkov • Shower produce intense colimated beam • Events with a large fraction of Čerenkov light are interesting because they allow us to: • See further away • Improve horizontal ν search • Study Čerenkov properties • A(α) – Lateral Distribution Function of Čerenkov

  25. Extensive Air Shower (EAS) Physics Exploring High Energy Hadronic Models… • Phenomenological Approach • Extrapolate from accelerator energies to several orders of magnitude above Models New models and possible high energy effects…

  26. String Percolation • As energy increases the number of sea strings increases • Strings overlap and fuse creating more energetic strings with higher length in rapidity • Create faster particles • Change the type of the leading particle • In EAS: • Change number of muons • Change the Xmax But how important are valence quarks??

  27. Net-Baryon ( Simple Model ) • Net-Baryon is • Two step-scenario Model • String Formation • Valence quarks • Energy obtained from PDFs • Parameter Q2 (√s) • String Fragmentation • String decays into a meson and a baryon • Kinematic Constraints

  28. Net-Baryon Results • Usual Models have problems explaining the data • Effective Q2 obtained from fit to data • Evolution with energy is a consequence of QCD evolution of the PDFs and the kinematic constraints in the string fragmentation • Simple model can reproduce Net-Baryon main features • Our model shows that the role of the Net-Baryon is not negligible

  29. Conclusions • Auger opens new windows in: • Astrophysics • Particle Physics • The LIP group has an active and enthusiastic participation!!

  30. A little bonus…

More Related