James M. Matthews, Ph.D.

James M. Matthews, PhD
Professor of Physics

Ph.D., 1984 - University of Wisconsin-Madison

Louisiana State University
Department of Physics & Astronomy
347 Nicholson Hall, Tower Dr.
Baton Rouge, LA 70803-4001
(225) 578-8598-Office

Research Interests

Experimental Astrophysics/Particle Physics

Pierre Auger Observatory

My research involves the experimental study of the highest energy cosmis rays. My group and I are engaged in several areas of hardware, electronics, and computer simulations for the new Pierre Auger Observatory. This project is an international collaboration of over 100 scientists and engineers.

The goal of the Pierre Auger Project is to measure the energy direction, and composition of the highest energy (> 10¹⁹ eV) cosmic rays. No known mechanism can fully account for the acceleration of cosmic rays to such high energies. Their extreme energy ensures that they suffer little deflection when passing through relatively weak Galactic or intergalactic magnetic fields. Cosmic rays also may interact with the cosmic background radiation, so any observed at earth must have originated at distances within about 100 Mpc. Few possible sources exist so nearby.

The near-linearity of trajectories and closeness of their origins make possible point-source astronomy with high energy cosmic rays. Accurate reconstruction of the axes of air showers produced in the earth's atmosphere by these cosmic rays should indicate their celestial source(s).

In the last forty years, only 14 cosmic ray events above 10²⁰ eV have been observed (An excellent recent review of the field has been given by M. Nagano and A.A. Watson, Rev. Mod. Phys. 72, 689 (2000)). Definitive study of such a very low flux demands a significant increase in aperture over present observatories. The collecting power of Auger is such that about 30 events above 10²⁰ eV should be observed per year, based on flux estimates from prior experiments. Auger will achieve nearly uniform sky coverage with two separated observatories, one each in the northern and southern hemispheres. Each installation has a surface array of particle detectors extending over 1600 square miles. On clear moonless nights, events also will be observed by fluorescence telescopes.

Construction of the Observatory began in Argentina in 1999. The central laboratory buildings and the first fluorescence detector are being built. The first instrumented surface detector tanks are in place and under study. The northern site, in central Utah, will begin construction in 2002

Current and Selected Publications

• B. Fick, et al., by the Pierre Auger Collaboration, "The Central laser facility at the Pierre Auger Observatory," JINST 1, P11003 (2006).

• D. Saltzberg, et al., "Introduction to the SalSA, a saltdome shower array as a GZK neutrino observatory," Abstract only - not a full paper. Prepared for International Workshop on Acoustic and Radio EeV Neutrino Detection Activities (ARENA 05), Zeuthen, Germany, 17-19 May 2005, Int. J. Mod.Phys. A 21S1, 252-253 (2006). Also in Zeuthen 2005, Acoustic and radio EeV neutrino detection activities 252-253.

• M. Aglietta, et al., by the Pierre Auger Collaboration, "Anisotropy studies around the Galactic Centre at EeV energies with the Auger Observatory, Astropart. Phys. 27, 244-253 (2007).
  e-Print: astro-ph/0607382

• J. Abraham, et al., by the Pierre Auger Collaboration, "An upper limit to the photon fraction in cosmic rays above 10**19-eV from the Pierre Auger Observatory," Astropart. Phys. 27, 155-168 (2007).
  e-Print: astro-ph/0606619

• J. Matthews, et al., by the Pierre Auger Collaboration, "A description of some ultrahigh energy cosmic rays observed with the Pierre Auger Observatory," presented at 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3-11 August 2005.

• J. Matthews, "A Heitler model of extensive air showers," Astropart. Phys. 22, 387-397 (2005).