Collisions in CMS !!!

CMS and the other LHC experiments have seen the first LHC collisions ever!

One of the very first CMS Collision Events at 900 GeV

You can clearly see a slew of green tracks coming from the interaction point. They are all straight because the magnetic field is off today. (It will be turned on later – remember that the experimental solenoids affect the beam so the LHC operators have do carry out careful measurements to compensate for these effects – to be done asap.) You can also see energy registered in the calorimetry (red is the hadronic calorimeter, and blue is the electromagnetic calorimeter). There are no muons in this event, and muons are not expected in this kind of minimum bias event. (They may appear as a consequence of the decays of pions and kaons – more about that later.)

I need to board my flight now (I am en route back to my home institution) – see Darin Acosta’s log for good, real-time reporting of what his happing in the CMS experiment.

This is a wonderful, wonderful day!