The first 7 TeV (3.5 TeV + 3.5 TeV) collisions took place on 30th March 2010, starting around 1pm local (Geneva) time and lasting for about 3.5 hours. Read the CERN Press Release here.
After the success of the LHC restart in late 2009, the machine had its first Technical Shutdown over the Christmas period, lasting until the end of February.
On 14th December, just 3 weeks after its restart, the LHC collided 1.18TeV beams of protons in CMS for the first time. During this first period more than 15000 2.36 TeV collision events were accumulated by CMS.
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".
The CMS Collaboration probes decays of the Z boson which would defy our expectations of lepton behavior
CMS sees evidence of the Upsilon meson decaying into two tau leptons for the first time at a hadron collider