W-boson decay

Display of a candidate W→μν event using proton-proton collisions at 7 TeV centre-of-mass energy at the LHC. Starting from the center of the ATLAS detector, the reconstructed tracks of the charged particles in the Inner Detector (ID) are shown as cyan lines. The energy deposits in the electromagnetic (the green layer) and hadronic (the red layer) calorimeters are shown as yellow boxes. The identified muon is shown with its reconstructed track (blue line) passing through the muon chambers (blue layers). The muon has a transverse momentum of 36 GeV, whereas the missing transverse energy (red arrow) is 35 GeV and corresponds to the muon neutrino energy. The transverse mass of the W boson candidate is 71 GeV.