The neutron is composed of two down quarks and an up quark and is stable under the strong and electromagnetic interactions. The weak interaction, however, can convert a down quark into an up quark ...

A free neutron outside a nucleus is not stable. It undergoes beta decay at a probability. Over time, the number of free neutrons decreases exponentially at a time constant, which is called the neutron ...

Neutron stars harbor some of the most extreme environments in the universe: their densities soar to several times those of atomic nuclei, and they possess some of the strongest gravitational fields of ...