What is particle decay and why does it occur?

Particle decay is the process by which a particle transforms into one or more other particles.

Particle decay occurs due to the instability of certain particles, which have excess energy or are not in their lowest energy state. These particles can decay spontaneously, emitting other particles in the process. The decay can also be induced by external factors such as collisions with other particles or exposure to high-energy radiation.

There are several types of particle decay, including alpha decay, beta decay, and gamma decay. In alpha decay, a nucleus emits an alpha particle (consisting of two protons and two neutrons) and transforms into a nucleus with a lower atomic number. In beta decay, a neutron in the nucleus decays into a proton and emits an electron or a positron, resulting in a change in atomic number. Gamma decay involves the emission of a gamma ray, which is a high-energy photon, from an excited nucleus.

Particle decay plays a crucial role in nuclear physics and particle physics, as it allows scientists to study the properties of particles and their interactions. Understanding particle decay is also important in fields such as medical imaging, where gamma rays are used in techniques such as PET scans.