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Decay signatures
When particles are able to travel a measurable distance in the bubble chamber before they decay, it is often possible to recognize them from an analysis of the tracks made by their decay products – which show up as 'vees’ and 'kinks’.
In addition, it is helpful to know that
- Electrons
and positrons 
can be recognized because they spiral and sometimes produce identifiable
bremsstrahlung photons which can 'materialise'
to pairs in the field of a nucleus (click
here). - Dark (sometimes short) tracks are very often produced by slow protons.
The following are sketches of the decay signatures that can occur, enabling us to identify certain particles. Depending on the momenta involved (given by the curvature of the tracks), these basic shapes may be somewhat distorted, but their topologies – defined by the vees and kinks – will remain.
There will be several references to the fact that whether or not a particular signature (eg. a vee) occurs will depend on chance – emphasizing the statistical nature of quantum phenomena (decays in our case).
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For a summary of the decay properties of the most commonly produced particles in bubble chambers, click here.
Very often, particles leave the bubble chamber without revealing their identities - making it impossible to say what happened just by looking at the picture.
To extract as much information as possible from the pictures it is necessary to measure them, and analyze the results.