On 23rd November the LHC collided 450 GeV beams of protons for the first time (see here) but only for a short period as a trial. The first real period of collisions started on 6th December.
Following the "splash" events of 6th/7th November (see here) the time has come to circulate the proton beams all around the LHC.
On the weekend of 6th & 7th November the LHC beam was injected and arrived near the CMS experiment, before being "stopped" by a large amount of material known as a "collimator".
CMS sees evidence of the Upsilon meson decaying into two tau leptons for the first time at a hadron collider