Which particle is primarily associated with alpha decay?

Alpha decay is a type of radioactive decay in which an unstable nucleus releases an alpha particle to become more stable. An alpha particle consists of two protons and two neutrons, which is essentially the same as a helium nucleus. Therefore, it can be correctly identified with a helium atom since the emission of an alpha particle transforms the original atom into a new element, typically resulting in a lower atomic number.

In the case of alpha decay, the ejected particle (the alpha particle) is directly related to the helium atom, making it a fundamental player in this type of decay process. Thus, identifying the particle primarily associated with alpha decay as a helium atom aligns with the definition and characteristics of the alpha particle involved in the nuclear reaction.