The simplified model below shows the reactants and products of a proton-antiproton reaction which produces three particles called pions, each having a different charge.
There are no other products in this process, which involves only the rearrangement of quarks. No electromagnetic radiation is produced. Assume that the initial kinetic energy of the proton and antiproton is negligible.
Protons consist of two up quarks
The following tables provide information about hadrons and quarks.
Table 1: Hadron Information
Table 2: Quark charges
- Identify the quarks present in the
and the particles. (2 marks)
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- The energy released in the reaction is shared equally between the pions.
- Calculate the energy released per pion in this reaction. (2 marks)
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- Calculation of the pions' velocities using classical physics predicts that each pion has a velocity, relative to the point at which the proton-antiproton reaction occurred, which exceeds 3 × 10
m s . - Explain the problem with this prediction and how it can be resolved. (3 marks)
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