The spiraling pattern on the left is from the electron that was knocked out by the muon.
On the right you see a looping clockwise pattern formed by the lightest positive pion.
Particles can be classified as positive or negative depending on whether they are spiraling in a clockwise or counterclockwise direction. The curvature of the spiral depends on the ratio of charge to mass. The electron?s spiral is so tight because the electron has a low mass; the track of the positive pion bends more slowly because it has greater mass.