Subatomic particle
= Subatomic particle
{wiki}
A <subatomic particle> is a constituent or excitation studied at the level below ordinary atomic structure. The category includes <elementary particles>, such as the <electron>, and composite <hadrons>, such as the <proton> and <neutron>.
Calling something a particle does not require a tiny classical solid sphere. <Quantum mechanics> describes localized detections and wave-like propagation, while high-energy scattering probes whether internal structure is resolved. A <particle detector> usually infers a particle from transferred <energy>, emitted light or a trajectory reconstructed from many interactions. The measured track width and the particle's intrinsic spatial structure are therefore different quantities.