Elementary particle

thumb|300px|Elementary particles included in the Standard Model. In particle physics, an elementary particle or fundamental particle is a particle whose substructure (domain of the bigger structure which shares the similar characteristics of the domain) is unknown, thus it is unknown whether it is composed of other particles. Quotes One of the most natural questions when one looks at the mass of uncorrelated data on elementary particle interactions is whether a systematic pattern is emerging from this complexity. The penetration of controlled laboratory experiments into the multi-Bev energy region can only make such a question more acute. R. E. Behrends, J. Dreitlein, C.Fronsdal and W. Lee, "Simple groups and strong interaction symmetries", Revs. Modern Phys. (1962) The arrangement into Generation (particle physics) families at least gives some semblance of order, but innumerable "whys" leap to the fore. Why are there so many fundamental particles, especially when it seems that the great majority of things in the world around us need only electrons, Up quark up-quarks, and Down quark down-quarks? Why are there three families? Why not one family or four families or any other number? Why do the particles have a seemingly random spread of masses—why, for instance, does the Tau (particle) tau weigh about 3,500 times as much as an electron? Why does the top quark weigh about 40,200 times as much as an up-quark? Brian Greene, Chapter 1. Tied Up with String The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory 25th anniversary edition W. W. Norton & Company 2024 9781324066248 https://books.google.com/books?id=4SnjEAAAQBAJ&pg=PT17 (496 pages; 1st edition 1999) It's a remarkable fact that matter at the subatomic level consists of tiny chunks, with vast empty spaces in between. Even more remarkable, these tiny chunks come in a small number of different types (electrons, protons, neutrons, pi mesons, neutrinos, and so on), which are then replicated in astronomical quantities to make all the "stuff" around us. And these replicas are absolutely perfect copies—not just "pretty similar," like two Fords coming off the same assembly line, but utterly indistinguishable. David Griffiths, Introduction to Elementary Particles https://books.google.com/books?id=Wb9DYrjcoKAC&pg=PA1 1 26 September 2008 John Wiley & Sons 978-3-527-61847-7 Even with our best understanding in traditional physics, there are dozens of different things that we can call elementary particles. The idea of string theory is to get all the different elementary particles — muons, neutrinos, electrons, up quarks, gluons, and so on — as different states of vibration of one basic string. Edward Witten, ICTP-SAIFR Strings 2021 - June 27 - Ask a String Theorist ICTP-SAIFR Strings 2021, YouTube https://www.youtube.com/watch?v=WwmxaXTnGMI (quote at 43:57 of 1:34:25) External links Category:Physics