Presented for Arnulfo Zepeda On behalf of the Mexican Collaboration

1. PHYSICS AND ASTROPHYSICS OF ULTRA HIGH ENERGY COSMIC RAYS BUAP CINVESTAV UMSNH UNAM Presented for Arnulfo Zepeda On behalf of the Mexican Collaboration Material selected and prepared for Rebeca López Sep. 2000

2. GOAL • To develop physics and astrophysics of ultra high energy cosmic rays through the participation of Mexican scientists in the construction of the Pierre Auger Observatory. R. López

3. CONTENTS • Antecedents on cosmic rays. • The Pierre Auger Observatory. • The Mexican Participation (this proposal). R. López

4. ANTECEDENTSSome major discoveries made with cosmic rays • The positron (the first antimatter sample), 1933. • Extended air showers, 1938. • The muon (first relative of the electron), 1943. • The pion (the carrier of nuclear interactions, postulated by Yukawa), 1947. • Particles with strangeness, 1947. R. López

5. Technics for detection of cosmic rays

6. Cosmic rays are produced in explosive astrophysical events. The low and medium energy spectrum is reasonable weel understood. COSMIC RAY FLUX R. López

8. The complete diffuse background radiation over the spectral region 10-9-1020 eV.

10. ULTRA HIGH ENERGY COSMIC RAYS • Cosmic rays may be produced with ultra high energy in exotic sources. • They may be further accelerated in strong magnetic fields and plasma shock waves. • Then they travel in the interstellar medium, which is never empty. R. López

12. Possible sources of high energy cosmic rays

13. Possible sources of high energy cosmic rays

14. XZ Tauri

15. HH 30

16. ULTRA HIGH ENERGY COSMIC RAYS • The interstellar medium is filled with low density radiation, the cosmic microwave background radiation, which originated during the early live of the Universe, at the time of the formation of atoms, at about 400,000 years after its birth. • Cosmic rays interact with the CMBR and if their energy is high enough, then their energy materializes into matter, pions are produced with high probability. Thus high energy cosmic rays loose soon their energy. R. López

19. PROCESSES ON THE CMBR

21. THE GZK CUTOFF • There is a limit, at around 5 X 1019 eV to the energy with which cosmic rays may arrive to the Earth from far away (50 Megaparsecs) This is the GZK cutoff. R. López

23. AGASA Energy Spectrum

24. Implications of events beyond the GZK cutoff • Suggest the existence of exotic sources? - Quasi-stable massive particles. - Supersymmetric matter. - Topological defects. • Violation of Lorentz invariance? R. López

25. EXPOSURES OF UHECR DETECTORS. R. López

26. EXPOSURES OF UHECR DETECTORS. R. López

27. PIERRE AUGER OBSERVATORY R. López

28. The shower

29. MAIN OBJECTIVE OF THE PIERRE AUGER OBSERVATORY • To understand the origin and nature of the ultra high energy cosmic rays, one of the major mysteries of modern physics. R. López

30. GOALS OF THE PIERRE AUGER OBSERVATORY • Detect a good number of ultra high energy events. • Measure with precision the energy of the primary cosmic particle. • Determine the incoming direction. • Identify the nature, type of particle. R. López

31. Consequences of the Pierre Auger Observatory data • In astrophysics. • In the theory of elementary particles. R. López

32. Hybrid Detector

35. How water Cherenkov detectors work

37. SCHEME OF THE FLUORESCENCE DETECTOR R. López

41. SIMULATION • The computer simulation of - The shower - The detectors - The electronics • Shows that the designed observatory will fulfill its objectives. R. López

42. Sites of the Pierre Auger Observatory  

43. Auger Observatory Exposure Sky as seen by observatories, 60° max shower zenith angle. North --> red, South --> green.

45. Pampa Amarilla Site

46. On March 17th 1999 work at the site in Mendoza began. Construction will continue till 2003 although observations will begin by 2001 R. López

47. The first water Cherenkov detector in Malargue

48. Plan of a Fluorescence Detector Building.

49. Los Leones R. López

50. Construction of the Central Station Building.