Answer:
Particle physics
Step-by-step explanation:
The field of physics that studies particles smaller than the atom is called "particle physics" or "high-energy physics". It is concerned with the study of the fundamental constituents of matter and the interactions between them at extremely high energies. Particle physics investigates the properties and behavior of particles such as quarks, leptons, and bosons, as well as the forces that govern their interactions. Particle accelerators, such as the Large Hadron Collider (LHC), are used to study particles at high energies and reveal the fundamental nature of the universe.