First of all, just as a particle has a position distribution in space, so does its momentum. Write the probability wave and use φ(p) instead of φ(r) to represent the probability density of momentum distribution. Here we just introduce a symbol by analogy.
Then write the inverse expression, that is, the expression of φ(p). It can be seen that the probability that the particle momentum is p is proportional to | φ (p) | 2, so the probability that the particle momentum is in a certain range can be obtained.
Extended data:
All kinds of particles have their own intrinsic properties, including mass m (stationary mass, expressed by energy), life τ (average life, which refers to the average life of a stationary system), charge q (in charge of protons), spin j (in thought), parity p, isospin I, isospin III, baryon number b, lepton number le, Lr and odd number.
Under the accuracy of existing experiments, lepton behaves like a point particle, without showing its internal structure, while hadron shows a composite particle with a certain structure. According to the viewpoint of modern particle physics, mesons consist of a pair of positive and negative quarks, baryons consist of three quarks, and leptons and quarks belong to the same level.
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