Longman Dictionary of Contemporary English
The Collaborative International Dictionary
Particle physics \Par"ti*cle phys`ics\, n. That branch of physics which investigates the nature of matter, and in particular the properties and behavior of the elementary particles (fundamental particles), of which matter is composed. Included in this field is the more specialized branch of high-energy physics.
Wiktionary
n. A branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them.
WordNet
n. the branch of physics that studies subatomic particles and their interactions [syn: high-energy physics, high energy physics]
Wikipedia
Particle physics (also high energy physics) is the branch of physics that studies the nature of the particles that constitute matter (particles with mass) and radiation (massless particles). 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 irreducibly fundamental force fields necessary to explain them. By our current understanding, these elementary particles are excitations of the quantum fields that also govern their interactions. The currently dominant theory explaining these fundamental particles and fields, along with their dynamics, is called the Standard Model. Thus, modern particle physics generally investigates the Standard Model and its various possible extensions, e.g. to the newest "known" particle, the Higgs boson, or even to the oldest known force field, gravity.
Usage examples of "particle physics".
The father was the late Luis Alvarez, a physicist who had won the 1968 Nobel Prize for his contributions to elementary particle physics.
He had described to them how, through the 1990s, he had worked in many areas of particle physics, his main specialty being the phenomenon of particle-antiparticle annihilation.
Although cloaked in the language of particle physics and quantum mechanics, the return to what was essentially a medieval worldview was complete, raising again all the metaphysical questions about what had come before the Bang.
A candidate particle physics laboratory had quickly emerged: Fermilab, outside Chicago, where Malenfant had a drinking-buddy relationship with the director.
I'm really just a hired hand, called in to verify some particle physics.
I work on the experimental side at Berkeley-high-energy particle physics.