Select a button and then choose a label from the 'control' panel on the left.The 'anti' button toggles between particles and anti-particles. Once you have filled in all three buttons the 'submit' button will become available.You can change a label simply by clicking a button and selecting a new label.
There is more than one correct combination of labels.You will be told how many labels (out of three) are correct upon submission.
This task will test your understanding of the production and decay of the top quark as
explained on the previous pages. A single lepton channel event is displayed, with buttons replacing the labels of three particle tracks.