Physics, Particles & Fields

"Particle physics is a branch of physics that studies the nature of particles that are the constituents of matter and radiation. Although the word particle can refer to various types of very small objects (e.g. protons, gas particles, or even household dust), "particle physics" usually investigates the irreducibly smallest detectable particles and the fundamental interactions necessary to explain their behaviour. By our current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions." - wikipedia