ar X iv : h ep - t h / 01 10 12 8 v 2 2 1 D ec 2 00 1 The particle invariance in particle physics

Since particles such as molecules, atoms and nuclei are composite particles, it is important to recognize that physics must be invariant for the composite particles and their constituent particles, this requirement is called particle invariance in this paper. But difficulties arise immediately because for fermion we use the Dirac equation, for meson we use the Klein-Gordon equation and for classical particle we use the Newtonian mechanics, while the connections between these equations are quite indirect. Thus if the particle invariance is hold in physics, i.e., only one physical formalism exists for any particle, we can expect to find out the differences between these equations by employing the particle invariance. As the results, several new relationships between them are found, the most important result is that the obstacles that cluttered the path from classical mechanics to quantum mechanics are found, it becomes possible to derive the quantum wave equations from the relativistic mechanics after the obstacles are removed. A improved model is proposed to gain a better understanding on elementary particle interactions. This approach offers enormous advantages, not only for giving the first physically reasonable interpretation of quantum mechanics, but also for improving the quark model.