Point-like particles
Definition: Particles in particle-physics modeled as having no spatial extension, internal structure, or volume (zero-dimensional).
The Standard Model
In the current standard-model, several fundamental particles are categorized as point-like:
- Quarks (e.g., up, down, charm, strange, top, bottom)
- Leptons (including electron, muon, and tau)
- Gauge bosons (e.g., gluon, W boson, Z boson)
- Higgs boson
Compositeness and Experimental Testing
A fundamental area of research involves testing the “elementary” nature of these particles to determine if they possess internal constituents (compositeness).
- Recent investigations, such as the LHC CMS Experiment Tests for Quark Substructure, specifically examine whether Quarks possess any internal structure.
- Experiments at the Large Hadron Collider (LHC) search for deviations from predicted scattering cross-sections that would indicate a non-zero radius or internal complexity.