When Hadrons Collide
Tuesday, December 1st, 2009Yesterday Back when I started writing this before Thanksgiving, the LHC saw its first collisions. Two counter rotating beams, colliding with a 900 GeV center of mass energy, with plans to ramp things up to 3.5 TeV per beam. Here GeV and TeV are metric prefixes meaning 10^9 and 10^12 respectively that you might be familiar with if you have gigabytes of RAM or terabytes of hard disk space.
More recently, they broke the record for the highest energy particle collision in an accelerator. Of course Earth-based accelerators will probably never reach the energies of high energy cosmic rays. The cosmic ray particles themselves have energies on the order of EeV (10^18). They are colliding with virtually stationary nitrogen nuclei, so to compare to the LHC target energies of about 7 TeV we’ll need to shift to the center of mass frame. There’s some really fun math here which I really want to go into more detail on sometime, but for right now I’ll just give you the back-of-the-envelope result and say that the cosmic ray energies exceed that by about 30 times.
Maybe it’s just because I’m working on a pretty slick cosmic ray observatory, but I think the next step in particle physics research is going to be based on studying theses naturally accelerated particles in new and creative ways, at least as a stepping stone on the way to the next generation of laboratory accelerators. Right now things are clearly a little tough, as it takes an array the size of the US state of Delaware to get about one high energy event per month. So the LHC still has us badly beaten in event rate, if not energy.