DOE has a long history of supporting research into fundamental particles. Five of the six types of quarks, one type of lepton, and all three neutrinos were discovered at what are now DOE national laboratories. Researchers supported by the DOE Office of Science, often in collaboration with scientists from around the world, have contributed to Nobel Prize-winning discoveries and measurements that refined the Standard Model. These efforts continue today, with experiments that make precision tests of the Standard Model and further improve measurements of particle properties and their interactions. Theorists work with experimental scientists to develop new avenues to explore the Standard Model. This research may also provide insight into what sorts of unknown particles and forces might explain dark matter and dark energy as well as explain what happened to antimatter after the big bang.
Particle physics (also known as high energy physics) is a branch of physics that studies the nature of the particles that constitute 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. 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.[1][2]
The idea that all matter is composed of elementary particles dates from at least the 6th century BC.[5] In the 19th century, John Dalton, through his work on stoichiometry, concluded that each element of nature was composed of a single, unique type of particle.[6] The word atom, after the Greek word atomos meaning "indivisible", has since then denoted the smallest particle of a chemical element, but physicists soon discovered that atoms are not, in fact, the fundamental particles of nature, but are conglomerates of even smaller particles, such as the electron. The early 20th century explorations of nuclear physics and quantum physics led to proofs of nuclear fission in 1939 by Lise Meitner (based on experiments by Otto Hahn), and nuclear fusion by Hans Bethe in that same year; both discoveries also led to the development of nuclear weapons. Throughout the 1950s and 1960s, a bewildering variety of particles were found in collisions of particles from increasingly high-energy beams. It was referred to informally as the "particle zoo". That term was deprecated[citation needed] after the formulation of the Standard Model during the 1970s, in which the large number of particles was explained as combinations of a (relatively) small number of more fundamental particles.
In principle, all physics (and practical applications developed therefrom) can be derived from the study of fundamental particles. In practice, even if "particle physics" is taken to mean only "high-energy atom smashers", many technologies have been developed during these pioneering investigations that later find wide uses in society. Particle accelerators are used to produce medical isotopes for research and treatment (for example, isotopes used in PET imaging), or used directly in external beam radiotherapy. The development of superconductors has been pushed forward by their use in particle physics. The World Wide Web and touchscreen technology were initially developed at CERN. Additional applications are found in medicine, national security, industry, computing, science, and workforce development, illustrating a long and growing list of beneficial practical applications with contributions from particle physics.[21]
Substantial motion is Mulla Sadra's philosophical innovation in material existence. Since the four fundamental interactions are the major topics of physics, in this comparative study, substantial motion is tested based on physical achievements. The study aimed to find answers to the following questions: do the achievements made in physics strengthen or weaken the theory of substantial motion? If science strengthens it, which physical interactions are examples of substantial motion? Based on the results of the physics, how can some of the accidental changes be considered as Substantial motion? Mulla Sadra proved that material existence has a constant inherent fluidity. Three centuries later, quantum physics proved the dynamism within matter. Mulla Sadra showed that accidental motion is the cause of substantial motion. Similarly, science confirmed that any change in the properties of an object results from the internal interactions of the matter and the object. Furthermore, any motion in an object occurs along with the exchange of the particles carrying force. Accordingly, internal transformations in the matter including the intermolecular, intramolecular, atomic, and subatomic (at elementary particles and quarks level) are subsets of the substantial motion.
Elementary particles are the fundamental objects of quantum field theory and are classified according to their spin and energy. The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including the gravitational force) in the universe, as well as classifying elementary particles. This model is based on quantizing classical fields, like electromagnetic fields, realizing that particles basically just emerge from excitations of these fields. For example these excitations have been mathematically modelled as an infinite system of coupled quantum harmonic oscillators and the characteristic energy spectrum is given by a ladder of evenly spaced energy levels, and each level in the ladder is identified by a number n, and the number of levels is infinite [1]. The masses of fundamental elementary particles have been calculated using the equation m/melectron = N/2Î, where Î is a coupling constant of quantum electrodynamics, but N is an arbitrary chosen integer variable [2]. A theoretical model considers particles as electromagnetic volume resonators, capable of holding electromagnetic waves of certain frequencies, based on resonance conditions for (self-acting) nonlinear electromagnetic waves, according to de Broglie waves [3]. Although the Standard Model is believed to be theoretically self-consistent and has demonstrated successes in providing experimental predictions, it leaves some phenomena unexplained. All masses of the elementary particles are still free parameters in the Standard model, all resulting from experimental results, and a physical formula for masses of elementary particles is not yet available.
All four fundamental forces are believed to be related, and an elegant feature is a unification of two of the four known forces into a single interaction [23]. According to Chris Neu efforts to devise a common theoretical framework that would explain the relation between the forces are perhaps the greatest goal of theoretical physicists today and the couplings of fundamental particles to the other particles are not yet all understood [23].
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