Yes, it is true, but “I read somewhere” isn’t a good reference. You should usually explicitly state where you read it.DiracPool said:I read somewhere that when, say, an electron and positron annihilate, they create two photons which travel in opposite directions in order to conserve linear momentum. Is this true?
Both energy and momentum must be conserved (as well as charge, spin, etc). So one photon cannot do it.DiracPool said:Do you likewise need two photons to do this? Or, can you do it with one photon provided it has enough energy?
Particle creation and annihilation refer to the process in which particles are created or destroyed in the universe. This can occur in various ways, such as through collisions, decays, or interactions with fields.
Particle creation and annihilation can occur through various mechanisms, such as pair production, where a particle and its antiparticle are created from a high-energy photon, or through particle decay, where a particle spontaneously transforms into other particles.
Particle creation and annihilation play a crucial role in understanding the fundamental laws of physics, such as quantum mechanics and the Standard Model. They also help explain the behavior of matter and energy in the universe.
Yes, particle creation and annihilation can be observed through experiments in high-energy particle physics, such as particle colliders, where particles are accelerated to high energies and their interactions are studied.
In most cases, particle creation and annihilation are reversible processes. However, there are some exceptions, such as in certain types of particle decays, where the initial and final states are not identical due to the conservation of certain properties, such as charge or lepton number.