If a neutron outside of the nucleus of an atom (also called a free neutron) were to decay into some other particles, what would these particles most likely to be? If all of the momentum of a matter...

If a neutron outside of the nucleus of an atom (also called a free neutron) were to decay into some other particles, what would these particles most likely to be?

If all of the momentum of a matter particle of mass mo and velocity v was transferred to a photon, what would the energy E of the photon be?