What's the most high-energy photon or particle discovered? Where are we in that?

[questionpost]

I googled it and got some particles with 5×10^19eV- 3.69×10^25eV-, but I know I've heard bigger somewhere else...

 

[Astronuc]

I googled it and got some particles with 5×10^19eV- 3.69×10^25eV-, but I know I've heard bigger somewhere else...

From where did one find those numbers. The number 5×10^19eV is frequently given in reference to the 'GZK cutoff' or 'GZK limit'.
http://en.wikipedia.org/wiki/Greisen–Zatsepin–Kuzmin_limit

There are some indications of particle energies in the 10²⁰ eV range.
http://en.wikipedia.org/wiki/Ultra-high-energy_cosmic_ray

One should review the following (and search for reliable information on Ultrahigh energy cosmis rays, or UHECR):
http://www.telescopearray.org/outreach/uhecr.html

http://arxiv.org/abs/1011.1872

http://www.slac.stanford.edu/econf/C040802/papers/L020.PDF

http://www.astro.ucla.edu/~rene/talks/Cronin-Fest-Ong-Writeup.pdf

http://uhecr.uchicago.edu/depot/uhecr-wp.pdf

http://canopus.chungnam.ac.kr/kaw3/00_PDF_kaw3/v37n5p421_jones.pdf


In terrestrial proton accelerators (synchrotrons), we get particles into the TeV (10¹² eV) range, but not quite to 10¹³ eV.

 

[questionpost]

I was thinking more around *10^27 and beyond...