A proton collides with an electron. What are the possible products of the collision?

When a proton collides with an electron, several outcomes are possible depending on the energy of the collision. Here are a few possibilities:

1. Elastic Scattering: If the energy of the collision is not very high, the proton and electron may simply bounce off each other. This is known as elastic scattering. The proton and electron remain as they were, but their directions of motion change.

2. Inelastic Scattering: If the energy of the collision is higher, the proton and electron may undergo inelastic scattering. In this case, the proton and electron still exist after the collision, but they may be in different energy states.

3. Pair Production: If the energy of the collision is extremely high (at least 1.022 MeV), the collision can produce a pair of particles: an electron and a positron (the antimatter counterpart of the electron). The original proton and electron still exist after the collision.

4. Annihilation: If a low-energy electron collides with a proton, it can be captured by the proton to form a neutron and a neutrino. This process is known as electron capture or K-capture.

Please note that the exact outcome of a proton-electron collision depends on many factors, including the energy of the particles and the specific conditions of the collision.