What defines an antiparticle?

An antiparticle is defined as a particle that has the same mass as its corresponding ordinary particle but possesses opposite charge and other quantum properties. For instance, the antiparticle of an electron, known as a positron, has the same mass as an electron but has a positive charge instead of a negative one. This relationship between particles and antiparticles is crucial in the field of particle physics, where interactions between them can lead to phenomena such as annihilation, resulting in the release of energy in the form of radiation.

The incorrect options highlight different properties or characteristics that do not accurately define an antiparticle. For example, a particle with no mass does not fit the definition, as all particles, including antiparticles, have mass. The notion that an antiparticle cannot interact with matter is also misleading; in reality, when an antiparticle encounters a particle, they can interact and annihilate each other. Lastly, while some particles emit radiation, it is not a defining characteristic of antiparticles specifically. Therefore, the focus on opposite properties alongside equal mass encapsulates the essential concept of what defines an antiparticle.