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Exercise 2

Not to be answered in the order written. All questions may not have a conclusive answer. This picture was taken in the CERN 2 metre bubble chamber, filled with hydrogen.

Looking at the summary of decay signatures and/or a table of particles properties might help. A good approach might be to list possibilities and try to find reasons to eliminate some of them.

If you want to get the questions in a more logical order, click here.

Questions:

• What needs to happen for a track to kink twice?
• What does the fact that you see a track indicate?
• How many vees are there?
• What is the charge of the beam?
• What are the small crosses?
• From which point comes the particles that cause the vees?
• In which direction is the beam going?
• How does the difference in mass between the initial state (before the kink) and the final state (after the kink) affect the angle of the kink?
• How many kinks are there?
• What causes a kink?
• What is the charge of the target particles?
• How many beam tracks are there?
• How can you tell if two tracks represent particles of the opposite charge?
• In which direction are the neutral particle(s) moving from the kinks?
• What particles can cause a vee?
• How many collisions are there?
• What causes a vee?
• What physical property of a particle is determined by the curvature of its track?

For answers to questions in logical order, click here.

For a powerpoint exercise click here.

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