The lambda produces a characteristic 'V' when it decays into a proton and a pi-minus.
It turns out that the charmed sigma particle only lasts a billionth of a second. We don?t see it; we only see the products of its decay. But by analyzing the number and properties of the particles produced, we can infer its existence. The discovery of this particle was an important step in establishing a new member of the quark family.
An incredible amount of important information, and cool physics, is in this single picture. Notice how closely the image and the schematic match, point by point. And how the picture tells the whole story using a very sophisticated visual language created by the underlying physics and the experimental design of the bubble chamber.