Related Research Articles
In physics, the fundamental interactions or fundamental forces are the interactions that do not appear to be reducible to more basic interactions. There are four fundamental interactions known to exist:
In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons. As a consequence of flavor and color combinations and antimatter, the fermions and bosons are known to have 48 and 13 variations, respectively. Among the 61 elementary particles embraced by the Standard Model number are electrons and other leptons, quarks, and the fundamental bosons. Subatomic particles such as protons or neutrons, which contain two or more elementary particles, are known as composite particles.
In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Fermions have a half-odd-integer spin and obey the Pauli exclusion principle. These particles include all quarks and leptons and all composite particles made of an odd number of these, such as all baryons and many atoms and nuclei. Fermions differ from bosons, which obey Bose–Einstein statistics.
A gluon is a type of massless elementary particle that mediates the strong interaction between quarks, acting as the exchange particle for the interaction. Gluons are massless vector bosons, thereby having a spin of 1. Through the strong interaction, gluons bind quarks into groups according to quantum chromodynamics (QCD), forming hadrons such as protons and neutrons.
In particle physics, a hadron is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules, which are held together by the electric force. Most of the mass of ordinary matter comes from two hadrons: the proton and the neutron, while most of the mass of the protons and neutrons is in turn due to the binding energy of their constituent quarks, due to the strong force.
Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the study of combination of protons and neutrons is called nuclear physics.
A quark is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. All commonly observable matter is composed of up quarks, down quarks and electrons. Owing to a phenomenon known as color confinement, quarks are never found in isolation; they can be found only within hadrons, which include baryons and mesons, or in quark–gluon plasmas. For this reason, much of what is known about quarks has been drawn from observations of hadrons.
The Standard Model of particle physics is the theory describing three of the four known fundamental forces in the universe and classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists worldwide, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, proof of the top quark (1995), the tau neutrino (2000), and the Higgs boson (2012) have added further credence to the Standard Model. In addition, the Standard Model has predicted various properties of weak neutral currents and the W and Z bosons with great accuracy.
In physics, a subatomic particle is a particle smaller than an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles, or an elementary particle, which is not composed of other particles. Particle physics and nuclear physics study these particles and how they interact. Most force carrying particles like photons or gluons are called bosons and, although they have discrete quanta of energy, do not have rest mass or discrete diameters and are unlike the former particles that have rest mass and cannot overlap or combine which are called fermions. The W and Z bosons, however, are an exception to this rule and have relatively large rest masses at approximately 80GeV and 90GeV respectively.
The up quark or u quark is the lightest of all quarks, a type of elementary particle, and a significant constituent of matter. It, along with the down quark, forms the neutrons and protons of atomic nuclei. It is part of the first generation of matter, has an electric charge of +2/3 e and a bare mass of 2.2+0.5
−0.4 MeV/c2. Like all quarks, the up quark is an elementary fermion with spin 1/2, and experiences all four fundamental interactions: gravitation, electromagnetism, weak interactions, and strong interactions. The antiparticle of the up quark is the up antiquark, which differs from it only in that some of its properties, such as charge have equal magnitude but opposite sign.
The down quark is a type of elementary particle, and a major constituent of matter. The down quark is the second-lightest of all quarks, and combines with other quarks to form composite particles called hadrons. Down quarks are most commonly found in atomic nuclei, where it combines with up quarks to form protons and neutrons. The proton is made of one down quark with two up quarks, and the neutron is made up of two down quarks with one up quark. Because they are found in every single known atom, down quarks are present in all everyday matter that we interact with.
The charm quark, charmed quark, or c quark is an elementary particle found in composite subatomic particles called hadrons such as the J/psi meson and the charmed baryons created in particle accelerator collisions. Several bosons, including the W and Z bosons and the Higgs boson, can decay into charm quarks. All charm quarks carry charm, a quantum number. This second generation particle is the third-most-massive quark with a mass of 1.27±0.02 GeV/c2 as measured in 2022 and a charge of +2/3 e.
In particle physics, annihilation is the process that occurs when a subatomic particle collides with its respective antiparticle to produce other particles, such as an electron colliding with a positron to produce two photons. The total energy and momentum of the initial pair are conserved in the process and distributed among a set of other particles in the final state. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of such an original pair are zero. Hence, any set of particles may be produced whose total quantum numbers are also zero as long as conservation of energy, conservation of momentum, and conservation of spin are obeyed.
In particle physics, the W and Z bosons are vector bosons that are together known as the weak bosons or more generally as the intermediate vector bosons. These elementary particles mediate the weak interaction; the respective symbols are
W+
,
W−
, and
Z0
. The
W±
bosons have either a positive or negative electric charge of 1 elementary charge and are each other's antiparticles. The
Z0
boson is electrically neutral and is its own antiparticle. The three particles each have a spin of 1. The
W±
bosons have a magnetic moment, but the
Z0
has none. All three of these particles are very short-lived, with a half-life of about 3×10−25 s. Their experimental discovery was pivotal in establishing what is now called the Standard Model of particle physics.
In particle physics, preons are hypothetical point particles, conceived of as sub-components of quarks and leptons. The word was coined by Jogesh Pati and Abdus Salam, in 1974. Interest in preon models peaked in the 1980s but has slowed, as the Standard Model of particle physics continues to describe physics mostly successfully, and no direct experimental evidence for lepton and quark compositeness has been found. Preons come in four varieties: plus, anti-plus, zero, and anti-zero. W bosons have six preons, and quarks and leptons have only three.
In particle physics, deep inelastic scattering is the name given to a process used to probe the insides of hadrons, using electrons, muons and neutrinos. It was first attempted in the 1960s and 1970s and provided the first convincing evidence of the reality of quarks, which up until that point had been considered by many to be a purely mathematical phenomenon. It is an extension of Rutherford scattering to much higher energies of the scattering particle and thus to much finer resolution of the components of the nuclei.
This timeline lists significant discoveries in physics and the laws of nature, including experimental discoveries, theoretical proposals that were confirmed experimentally, and theories that have significantly influenced current thinking in modern physics. Such discoveries are often a multi-step, multi-person process. Multiple discovery sometimes occurs when multiple research groups discover the same phenomenon at about the same time, and scientific priority is often disputed. The listings below include some of the most significant people and ideas by date of publication or experiment.
In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value. Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have odd half-integer spin. Every observed subatomic particle is either a boson or a fermion. Paul Dirac coined the name boson to commemorate the contribution of Satyendra Nath Bose, an Indian physicist.
The idea that matter consists of smaller particles and that there exists a limited number of sorts of primary, smallest particles in nature has existed in natural philosophy at least since the 6th century BC. Such ideas gained physical credibility beginning in the 19th century, but the concept of "elementary particle" underwent some changes in its meaning: notably, modern physics no longer deems elementary particles indestructible. Even elementary particles can decay or collide destructively; they can cease to exist and create (other) particles in result.
References
- ↑ Narayan, Rupa (2013). Space, Time and Anu in Vaisheshika (PDF). Louisiana State University, Baton Rouge, USA.
- ↑ Teresi, Dick (2010). Lost Discoveries: The Ancient Roots of Modern Science. Simon and Schuster. pp. 213–214. ISBN 978-1-4391-2860-2.
- ↑ Jammer, Max (1966), The conceptual development of quantum mechanics, New York: McGraw-Hill, OCLC 534562
- ↑ Tivel, David E. (September 2012). Evolution: The Universe, Life, Cultures, Ethnicity, Religion, Science, and Technology. Dorrance Publishing. ISBN 9781434929747.
- ↑ Gilbert N. Lewis. Letter to the editor of Nature (Vol. 118, Part 2, 18 December 1926, pp. 874–875).
- ↑ The origin of the word "photon"
- ↑ The Davisson–Germer experiment, which demonstrates the wave nature of the electron
- ↑ A. Abragam and B. Bleaney. 1970. Electron Parmagnetic Resonance of Transition Ions, Oxford University Press: Oxford, U.K., p. 911
- ↑ Feynman, R.P. (2006) [1985]. QED: The Strange Theory of Light and Matter . Princeton University Press. ISBN 0-691-12575-9.
- ↑ Richard Feynman; QED. Princeton University Press: Princeton, (1982)
- ↑ Richard Feynman; Lecture Notes in Physics. Princeton University Press: Princeton, (1986)
- ↑ Feynman, R.P. (2001) [1964]. The Character of Physical Law . MIT Press. ISBN 0-262-56003-8.
- ↑ Feynman, R.P. (2006) [1985]. QED: The Strange Theory of Light and Matter . Princeton University Press. ISBN 0-691-12575-9.
- ↑ Schweber, Silvan S.; Q.E.D. and the men who made it: Dyson, Feynman, Schwinger, and Tomonaga, Princeton University Press (1994) ISBN 0-691-03327-7
- ↑ Schwinger, Julian; Selected Papers on Quantum Electrodynamics, Dover Publications, Inc. (1958) ISBN 0-486-60444-6
- ↑
- Kleinert, H. (2008). Multivalued Fields in Condensed Matter, Electrodynamics, and Gravitation (PDF). World Scientific. ISBN 978-981-279-170-2.
- ↑ Yndurain, Francisco Jose; Quantum Chromodynamics: An Introduction to the Theory of Quarks and Gluons, Springer Verlag, New York, 1983. ISBN 0-387-11752-0
- 1 2 Frank Wilczek (1999) "Quantum field theory", Reviews of Modern Physics 71: S83–S95. Also doi=10.1103/Rev. Mod. Phys. 71.
- ↑ Englert, F.; Brout, R. (1964). "Broken Symmetry and the Mass of Gauge Vector Mesons". Physical Review Letters . 13 (9): 321–323. Bibcode:1964PhRvL..13..321E. doi: 10.1103/PhysRevLett.13.321 .
- ↑ Higgs, P.W. (1964). "Broken Symmetries and the Masses of Gauge Bosons". Physical Review Letters . 13 (16): 508–509. Bibcode:1964PhRvL..13..508H. doi: 10.1103/PhysRevLett.13.508 .
- ↑ Guralnik, G.S.; Hagen, C.R.; Kibble, T.W.B. (1964). "Global Conservation Laws and Massless Particles". Physical Review Letters . 13 (20): 585–587. Bibcode:1964PhRvL..13..585G. doi: 10.1103/PhysRevLett.13.585 .
- ↑ Guralnik, G.S. (2009). "The History of the Guralnik, Hagen and Kibble development of the Theory of Spontaneous Symmetry Breaking and Gauge Particles". International Journal of Modern Physics A . 24 (14): 2601–2627. arXiv: 0907.3466 . Bibcode:2009IJMPA..24.2601G. doi:10.1142/S0217751X09045431. S2CID 16298371.
- ↑ Kibble, T.W.B. (2009). "Englert–Brout–Higgs–Guralnik–Hagen–Kibble mechanism". Scholarpedia . 4 (1): 6441. Bibcode:2009SchpJ...4.6441K. doi: 10.4249/scholarpedia.6441 .
- ↑ M. Blume; S. Brown; Y. Millev (2008). "Letters from the past, a PRL retrospective (1964)". Physical Review Letters . Retrieved 30 January 2010.
- ↑ "J. J. Sakurai Prize Winners". American Physical Society. 2010. Retrieved 30 January 2010.
- ↑ Weinberg, Steven; The Quantum Theory of Fields: Foundations (vol. I), Cambridge University Press (1995) ISBN 0-521-55001-7. The first chapter (pp. 1–40) of Weinberg's monumental treatise gives a brief history of Q.F.T., pp. 608.
- ↑ Weinberg, Steven; The Quantum Theory of Fields: Modern Applications (vol. II), Cambridge University Press:Cambridge, U.K. (1996) ISBN 0-521-55001-7, pp. 489.
- ↑
- Gerard 't Hooft (2007) "The Conceptual Basis of Quantum Field Theory" in Butterfield, J., and John Earman, eds., Philosophy of Physics, Part A. Elsevier: 661-730.
- ↑ Wilczek, Frank (1999). "Quantum field theory". Reviews of Modern Physics. 71 (2): S85–S95. arXiv: hep-th/9803075 . Bibcode:1999RvMPS..71...85W. doi:10.1103/RevModPhys.71.S85. S2CID 279980.
- 1 2 3 "Fermilab | Science | Particle Physics | Key Discoveries". www.fnal.gov. Retrieved 26 August 2020.
- ↑ Pais, Abraham; Inward Bound: Of Matter & Forces in the Physical World, Oxford University Press (1986) ISBN 0-19-851997-4 Written by a former Einstein assistant at Princeton, this is a beautiful detailed history of modern fundamental physics, from 1895 (discovery of X-rays) to 1983 (discovery of vectors bosons at C.E.R.N.)
- ↑ Fukuda, Y.; et al. (Super-Kamiokande Collaboration) (24 August 1998). "Evidence for Oscillation of Atmospheric Neutrinos". Physical Review Letters. 81 (8): 1562–1567. arXiv: hep-ex/9807003 . Bibcode:1998PhRvL..81.1562F. doi:10.1103/PhysRevLett.81.1562.
- ↑ "Press Release: The 1999 Nobel Prize in Chemistry". 12 October 1999. Retrieved 30 June 2013.
- ↑ "New State of Matter created at CERN". CERN. Retrieved 22 May 2020.
- ↑ "Lene Hau". Physicscentral.com. Retrieved 30 January 2013.
- ↑ "RHIC Scientists Serve Up 'Perfect' Liquid". Brookhaven National Laboratory. Retrieved 26 August 2020.
- ↑ "CERN experiments observe particle consistent with long-sought Higgs boson". CERN. Retrieved 22 May 2020.
- ↑ LHCb Collaboration (4 June 2014). "Observation of the Resonant Character of the Z ( 4430 ) − State". Physical Review Letters. 112 (22): 222002. doi:10.1103/PhysRevLett.112.222002. hdl: 2445/133080 . PMID 24949760. S2CID 904429.
- ↑ T2K Collaboration (10 February 2014). "Observation of Electron Neutrino Appearance in a Muon Neutrino Beam". Physical Review Letters. 112 (6): 061802. arXiv: 1311.4750 . Bibcode:2014PhRvL.112f1802A. doi:10.1103/PhysRevLett.112.061802. hdl: 10044/1/20051 . PMID 24580687. S2CID 2586182.
- ↑ OPERA Collaboration (28 October 2014). "Observation of tau neutrino appearance in the CNGS beam with the OPERA experiment". Progress of Theoretical and Experimental Physics. 2014 (10): 101C01. arXiv: 1407.3513 . doi: 10.1093/ptep/ptu132 .
