A proton-proton collision candidate event. On November 23 protons from two beams circulated at LHC and have collided at LHCb. LHC news video youTube LHCb control room at this historical…

Animation (click on picture): pp collisions and proton beam gas collisions recorded on Nov. 23, 2009. Other reconstructed events can be found here.

pi0 is the short lived particle decaying into two photons which were measured in the electromagnetic calorimeter ECAL. The plot above shows the nearly perfectly reconstructed pi0 mass.

… reconstructed Vertex Locator VELO track. Other reconstructed events can be found here. … event reconstructed later (offline reconstruction). Particularly interesting is the blue track recorded in the Vertex Locator…

LHC has restarted on November 21st. Two LHC beams have made a full turn of the LHC. Afterwards, after synchronization with the LHC accelerating system (RF capture in technical language),…