In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. These particles obey the Pauli exclusion principle. Fermions include all quarks and leptons, as well as all composite particles made of an odd number of these, such as all baryons and many atoms and nuclei. Fermions differ from bosons. A fermion can be an elementary particle, such as the electron, or it can be a composite particle, such as the proton. According to the spin-statistics theorem in any reasonable relativistic quantum field theory, particles with integer spin are bosons, while particles with half-integer spin are fermions. In addition to the spin characteristic, fermions have another specific property: they possess conserved baryon or lepton quantum numbers. Therefore, what is referred to as the spin statistics relation is in fact a spin statistics-quantum number relation; as a consequence of the Pauli exclusion principle, only one fermion can occupy a particular quantum state at any given time. If multiple fermions have the same spatial probability distribution at least one property of each fermion, such as its spin, must be different.
Fermions are associated with matter, whereas bosons are force carrier particles, although in the current state of particle physics the distinction between the two concepts is unclear. Weakly interacting fermions can display bosonic behavior under extreme conditions. At low temperature fermions show superfluidity for uncharged particles and superconductivity for charged particles. Composite fermions, such as protons and neutrons, are the key building blocks of everyday matter; the name fermion was coined by English theoretical physicist Paul Dirac from the surname of Italian physicist Enrico Fermi. The Standard Model recognizes two types of elementary fermions: leptons. In all, the model distinguishes 24 different fermions. There are six quarks, six leptons, along with the corresponding antiparticle of each of these. Mathematically, fermions come in three types: Weyl fermions, Dirac fermions, Majorana fermions. Most Standard Model fermions are believed to be Dirac fermions, although it is unknown at this time whether the neutrinos are Dirac or Majorana fermions.
Dirac fermions can be treated as a combination of two Weyl fermions. In July 2015, Weyl fermions have been experimentally realized in Weyl semimetals. Composite particles can be fermions depending on their constituents. More because of the relation between spin and statistics, a particle containing an odd number of fermions is itself a fermion, it will have half-integer spin. Examples include the following: A baryon, such as the proton or neutron, contains three fermionic quarks and thus it is a fermion; the nucleus of a carbon-13 atom is therefore a fermion. The atom helium-3 is made of two protons, one neutron, two electrons, therefore it is a fermion; the number of bosons within a composite particle made up of simple particles bound with a potential has no effect on whether it is a boson or a fermion. Fermionic or bosonic behavior of a composite particle is only seen at large distances. At proximity, where spatial structure begins to be important, a composite particle behaves according to its constituent makeup.
Fermions can exhibit bosonic behavior. This is the origin of superconductivity and the superfluidity of helium-3: in superconducting materials, electrons interact through the exchange of phonons, forming Cooper pairs, while in helium-3, Cooper pairs are formed via spin fluctuations; the quasiparticles of the fractional quantum Hall effect are known as composite fermions, which are electrons with an number of quantized vortices attached to them. In a quantum field theory, there can be field configurations of bosons which are topologically twisted; these are coherent states which behave like a particle, they can be fermionic if all the constituent particles are bosons. This was discovered by Tony Skyrme in the early 1960s, so fermions made of bosons are named skyrmions after him. Skyrme's original example involved fields which take values on a three-dimensional sphere, the original nonlinear sigma model which describes the large distance behavior of pions. In Skyrme's model, reproduced in the large N or string approximation to quantum chromodynamics, the proton and neutron are fermionic topological solitons of the pion field.
Whereas Skyrme's example involved pion physics, there is a much more familiar example in quantum electrodynamics with a magnetic monopole. A bosonic monopole with the smallest possible magnetic charge and a bosonic version of the electron will form a fermionic dyon; the analogy between the Skyrme field and the Higgs field of the electroweak sector has been used to postulate that all fermions are skyrmions. This could explain why all known fermions have baryon or lepton quantum numbers and provide a physical mechanism for the Pauli exclusion principle
George Zweig is a Russian-American physicist. He was trained as a particle physicist under Richard Feynman, he introduced, independently of the quark model. He turned his attention to neurobiology, he has worked as a Research Scientist at Los Alamos National Laboratory and MIT, in the financial services industry. Zweig was born in Russia into a Jewish family, his father was a type of civil engineer known as a structural engineer. He graduated from the University of Michigan in 1959, with a bachelor's degree in mathematics, having taken numerous physics courses as electives, he earned a PhD degree in theoretical physics at the California Institute of Technology in 1964. Zweig proposed the existence of quarks at CERN, independently of Murray Gell-Mann, right after defending his PhD dissertation. Zweig dubbed them "aces", after the four playing cards, because he speculated there were four of them; the introduction of quarks provided a cornerstone for particle physics. Like Gell-Mann, he realized that several important properties of particles such as baryons could be explained by treating them as triplets of other constituent particles, with fractional baryon number and electric charge.
Unlike Gell-Mann, Zweig was led to his picture of the quark model by the peculiarly attenuated decays of the φ meson to ρ π, a feature codified by what is now known as the OZI Rule, the "Z" in which stands for "Zweig". In subsequent technical terminology Gell-Mann's quarks were closer to "current quarks", while Zweig's to "constituent quarks"; as pointed out by astrophysicist John Gribbin, Gell-Mann deservedly received the Nobel Prize for physics in 1969, for his overall contributions and discoveries concerning the classification of elementary particles and their interactions. In years, when quark theory became established as the standard model of particle physics, the Nobel committee felt they couldn't recognize Zweig as the scientist who first spelled out the theory's implications in detail and suggested that they might be real, without including Gell-Mann again. In 1977 Richard Feynman nominated both Gell-Mann and Zweig for the Nobel prize, presumed to be his only nomination for such. Whatever the reason, despite Zweig's contributions to a theory central to modern physics, he has not yet been awarded a Nobel prize.
Zweig turned to hearing research and neurobiology, studied the transduction of sound into nerve impulses in the cochlea of the human ear, how the brain maps sound onto the spatial dimensions of the cerebral cortex. In 1975, while studying the ear, he discovered a version of the continuous wavelet transform, the cochlear transform. In 2003, Zweig joined the quantitative hedge fund Renaissance Technologies, founded by the former Cold War code breaker James Simons, he left the firm in 2010. Once his four-year confidentiality agreement with Renaissance Technologies expired, the 78-year-old Zweig returned to Wall Street and co-founded a quantitative hedge fund, called Signition, with two younger partners, they hope to begin trading in 2015. Zweig was quoted as saying "life can be boring" without work. MacArthur Prize Fellowship National Academy of Sciences Sakurai Prize
Murray Gell-Mann is an American physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles. He is the Robert Andrews Millikan Professor of Theoretical Physics Emeritus at the California Institute of Technology, a distinguished fellow and co-founder of the Santa Fe Institute, a professor of physics at the University of New Mexico, the Presidential Professor of Physics and Medicine at the University of Southern California. Gell-Mann has spent several periods at CERN, among others as a John Simon Guggenheim Memorial Foundation fellow in 1972. Gell-Mann was born in lower Manhattan into a family of Jewish immigrants from the Austro-Hungarian Empire from Chernivtsi in present-day Ukraine, his parents were Arthur Isidore Gell-Mann, who taught English as a Second Language. Propelled by an intense boyhood curiosity and love for nature and mathematics, he graduated valedictorian from the Columbia Grammar & Preparatory School and subsequently entered Yale College at the age of 15 as a member of Jonathan Edwards College.
At Yale, he participated in the William Lowell Putnam Mathematical Competition and was on the team representing Yale University that won the second prize in 1947. Gell-Mann earned a bachelor's degree in physics from Yale in 1948 and a PhD in physics from Massachusetts Institute of Technology in 1951, his supervisor at MIT was Victor Weisskopf. In 1958, Gell-Mann and Richard Feynman, in parallel with the independent team of George Sudarshan and Robert Marshak, discovered the chiral structures of the weak interaction in physics; this work followed the experimental discovery of the violation of parity by Chien-Shiung Wu, as suggested by Chen Ning Yang and Tsung-Dao Lee, theoretically. Gell-Mann's work in the 1950s involved discovered cosmic ray particles that came to be called kaons and hyperons. Classifying these particles led him to propose that a quantum number called strangeness would be conserved by the strong and the electromagnetic interactions, but not by the weak interactions. Another of Gell-Mann's ideas is the Gell-Mann–Okubo formula, a formula based on empirical results, but was explained by his quark model.
Gell-Mann and Abraham Pais were involved in explaining several puzzling aspects of the physics of these particles. In 1961, this led him to introduce a classification scheme for hadrons, elementary particles that participate in the strong interaction; this scheme is now explained by the quark model. Gell-Mann referred to the scheme as the Eightfold Way, because of the octets of particles in the classification. In 1964, Gell-Mann and, George Zweig went on to postulate the existence of quarks, particles of which the hadrons of this scheme are composed; the name is a reference to the novel Finnegans Wake, by James Joyce. Zweig had referred to the particles as "aces". Quarks and gluons were soon established as the underlying elementary objects in the study of the structure of hadrons, he was awarded a Nobel Prize in physics in 1969 for his contributions and discoveries concerning the classification of elementary particles and their interactions. In 1972 he and Harald Fritzsch introduced the conserved quantum number "color charge", together with Heinrich Leutwyler, they coined the term quantum chromodynamics as the gauge theory of the strong interaction.
The quark model is a part of QCD, it has been robust enough to accommodate in a natural fashion the discovery of new "flavors" of quarks, which superseded the eightfold way scheme. He is the Robert Andrews Millikan Professor of Theoretical Physics Emeritus at California Institute of Technology as well as a University Professor in the Physics and Astronomy Department of the University of New Mexico in Albuquerque, New Mexico, the Presidential Professor of Physics and Medicine at the University of Southern California, he is a member of the editorial board of the Encyclopædia Britannica. In 1984 Gell-Mann co-founded the Santa Fe Institute—a non-profit theoretical research institute in Santa Fe, New Mexico—to study complex systems and disseminate the notion of a separate interdisciplinary study of complexity theory, he was a postdoctoral fellow at the Institute for Advanced Study in 1951, a visiting research professor at the University of Illinois at Urbana–Champaign from 1952 to 1953. He was a visiting associate professor at Columbia University and an associate professor at the University of Chicago in 1954–55 before moving to the California Institute of Technology, where he taught from 1955 until he retired in 1993.
During the 1990s, Gell-Mann's interest turned to the emerging study of complexity. He played a central role in the founding of the Santa Fe Institute, where he continues to work as a distinguished professor, he wrote a popular science book about these matters, The Quark and the Jaguar: Adventures in the Simple and the Complex. The title of the book is taken from a line of a poem by Arthur Sze: "The world of the quark has everything to do with a jaguar circling in the night"; the author George Johnson has written a biography of Gell-Mann, Strange Beauty: Murray Gell-Mann, the Revolution in 20th-Century Physics, shortlisted for the Royal Society Book Prize. Gell-Mann has criticized it as inaccurate; the Nobel Prize–winning physicist Philip Anderson, in his chapter on Gell-Mann from a 2011 book, says that Johnson's biography is excellent. Both Anderso
Reductionism is any of several related philosophical ideas regarding the associations between phenomena which can be described in terms of other simpler or more fundamental phenomena. The Oxford Companion to Philosophy suggests that reductionism is "one of the most used and abused terms in the philosophical lexicon" and suggests a three part division: Ontological reductionism: a belief that the whole of reality consists of a minimal number of parts. Methodological reductionism: the scientific attempt to provide explanation in terms of smaller entities. Theory reductionism: the suggestion that a newer theory does not replace or absorb an older one, but reduces it to more basic terms. Theory reduction itself is divisible into three parts: translation and explanation. Reductionism can be applied to any phenomenon, including objects, explanations and meanings. For the sciences, application of methodological reductionism attempts explanation of entire systems in terms of their individual, constituent parts and their interactions.
For example, the temperature of a gas is reduced to nothing beyond the average kinetic energy of its molecules in motion. Thomas Nagel speaks of'psychophysical reductionism', as do others and'physico-chemical reductionism', again as do others. In a simplified and sometimes contested form, such reductionism is said to imply that a system is nothing but the sum of its parts. However, a more nuanced opinion is that a system is composed of its parts, but the system will have features that none of the parts have. "The point of mechanistic explanations is showing how the higher level features arise from the parts."Other definitions are used by other authors. For example, what John Polkinghorne terms'conceptual' or'epistemological' reductionism is the definition provided by Simon Blackburn and by Jaegwon Kim: that form of reductionism concerning a program of replacing the facts or entities entering statements claimed to be true in one type of discourse with other facts or entities from another type, thereby providing a relationship between them.
Such an association is provided where the same idea can be expressed by "levels" of explanation, with higher levels reducible if need be to lower levels. This use of levels of understanding in part expresses our human limitations in remembering detail. However, "most philosophers would insist that our role in conceptualizing reality does not change the fact that different levels of organization in reality do have different'properties'."Reductionism represents a certain perspective of causality. In a reductionist framework, the phenomena that can be explained in terms of relations between other more fundamental phenomena, are termed epiphenomena. There is an implication that the epiphenomenon exerts no causal agency on the fundamental phenomena that explain it; the epiphenomena are sometimes said to be "nothing but" the outcome of the workings of the fundamental phenomena, although the epiphenomena might be more and efficiently described in different terms. There is a tendency to avoid considering an epiphenomenon as being important in its own right.
This attitude may extend to cases where the fundamentals are not able to explain the epiphenomena, but are expected to by the speaker. In this way, for example, morality can be deemed to be "nothing but" evolutionary adaptation, consciousness can be considered "nothing but" the outcome of neurobiological processes. Reductionism should be distinguished from eliminationism: reductionists do not deny the existence of phenomena, but explain them in terms of another reality. For example, eliminationists deny the existence of life by their explanation in terms of physical and chemical processes. Reductionism does not preclude the existence of what might be termed emergent phenomena, but it does imply the ability to understand those phenomena in terms of the processes from which they are composed; this reductionist understanding is different from emergentism, which intends that what emerges in "emergence" is more than the sum of the processes from which it emerges. Most philosophers delineate three types of anti-reductionism.
Ontological reductionism is the belief that reality is composed of a minimum number of kinds of entities or substances. This claim is metaphysical, is most a form of monism, in effect claiming that all objects and events are reducible to a single substance. Richard Jones divides ontological reductionism into two: the reductionism of substances and the reduction of the number of structures operating in nature; this permits scientists and philosophers to affirm the former while being anti-reductionists regarding the latter. Nancey Murphy has claimed that there are two species of ontological reductionism: one that denies that wholes are anything more than their parts, she admits that the phrase "really real" is senseless but nonetheless has tried to explicate the supposed difference between the two. Ontological reductionism denies the idea of ontological emergence, claims that emergence is an epistemological phenomenon that only exists through analysis or de
Mass is both a property of a physical body and a measure of its resistance to acceleration when a net force is applied. The object's mass determines the strength of its gravitational attraction to other bodies; the basic SI unit of mass is the kilogram. In physics, mass is not the same as weight though mass is determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less than it does on Earth because of the lower gravity, but it would still have the same mass; this is because weight is a force, while mass is the property that determines the strength of this force. There are several distinct phenomena. Although some theorists have speculated that some of these phenomena could be independent of each other, current experiments have found no difference in results regardless of how it is measured: Inertial mass measures an object's resistance to being accelerated by a force. Active gravitational mass measures the gravitational force exerted by an object.
Passive gravitational mass measures the gravitational force exerted on an object in a known gravitational field. The mass of an object determines its acceleration in the presence of an applied force; the inertia and the inertial mass describe the same properties of physical bodies at the qualitative and quantitative level by other words, the mass quantitatively describes the inertia. According to Newton's second law of motion, if a body of fixed mass m is subjected to a single force F, its acceleration a is given by F/m. A body's mass determines the degree to which it generates or is affected by a gravitational field. If a first body of mass mA is placed at a distance r from a second body of mass mB, each body is subject to an attractive force Fg = GmAmB/r2, where G = 6.67×10−11 N kg−2 m2 is the "universal gravitational constant". This is sometimes referred to as gravitational mass. Repeated experiments since the 17th century have demonstrated that inertial and gravitational mass are identical.
The standard International System of Units unit of mass is the kilogram. The kilogram is 1000 grams, first defined in 1795 as one cubic decimeter of water at the melting point of ice. However, because precise measurement of a decimeter of water at the proper temperature and pressure was difficult, in 1889 the kilogram was redefined as the mass of the international prototype kilogram of cast iron, thus became independent of the meter and the properties of water. However, the mass of the international prototype and its identical national copies have been found to be drifting over time, it is expected that the re-definition of the kilogram and several other units will occur on May 20, 2019, following a final vote by the CGPM in November 2018. The new definition will use only invariant quantities of nature: the speed of light, the caesium hyperfine frequency, the Planck constant. Other units are accepted for use in SI: the tonne is equal to 1000 kg. the electronvolt is a unit of energy, but because of the mass–energy equivalence it can be converted to a unit of mass, is used like one.
In this context, the mass has units of eV/c2. The electronvolt and its multiples, such as the MeV, are used in particle physics; the atomic mass unit is 1/12 of the mass of a carbon-12 atom 1.66×10−27 kg. The atomic mass unit is convenient for expressing the masses of molecules. Outside the SI system, other units of mass include: the slug is an Imperial unit of mass; the pound is a unit of both mass and force, used in the United States. In scientific contexts where pound and pound need to be distinguished, SI units are used instead; the Planck mass is the maximum mass of point particles. It is used in particle physics; the solar mass is defined as the mass of the Sun. It is used in astronomy to compare large masses such as stars or galaxies; the mass of a small particle may be identified by its inverse Compton wavelength. The mass of a large star or black hole may be identified with its Schwarzschild radius. In physical science, one may distinguish conceptually between at least seven different aspects of mass, or seven physical notions that involve the concept of mass.
Every experiment to date has shown these seven values to be proportional, in some cases equal, this proportionality gives rise to the abstract concept of mass. There are a number of ways mass can be measured or operationally defined: Inertial mass is a measure of an object's resistance to acceleration when a force is applied, it is determined by applying a force to an object and measuring the acceleration that results from that force. An object with small inertial mass will accelerate more than an object with large inertial mass when acted upon by the same force. One says. Active gravitational mass is a measure of the strength of an object's gravitational flux. Gravitational field can be measured by allowing a small "test object" to fall and measuring its free-fall acceleration. For example, an object in free fall near the Moon is subject to a smaller gravitational field, hence
Mohammad Abdus Salam, was a Pakistani theoretical physicist. He shared the 1979 Nobel Prize in Physics with Sheldon Glashow and Steven Weinberg for his contribution to the electroweak unification theory, he was the first Pakistani to receive a Nobel Prize in science and the second from an Islamic country to receive any Nobel Prize. Salam was science advisor to the Ministry of Science and Technology in Pakistan from 1960 to 1974, a position from which he was supposed to play a major and influential role in the development of the country's science infrastructure. Salam contributed to developments in theoretical and particle physics, he was the founding director of the Space and Upper Atmosphere Research Commission, responsible for the establishment of the Theoretical Physics Group in the Pakistan Atomic Energy Commission. As Science Advisor, Salam played a role in Pakistan's development of the peaceful use of nuclear energy, may have contributed as well to development of atomic bomb project of Pakistan in 1972.
In 1974, Abdus Salam departed from his country, in protest, after the Parliament of Pakistan passed unanimously a parliamentary bill declaring members of the Ahmadiyya movement to which Salam belonged non-Muslims. In 1998, following the country's nuclear tests, the Government of Pakistan issued a commemorative stamp, as a part of "Scientists of Pakistan", to honour the services of Salam. Salam's notable achievements include the Pati–Salam model, magnetic photon, vector meson, Grand Unified Theory, work on supersymmetry and, most electroweak theory, for which he was awarded the Nobel Prize. Salam made a major contribution in quantum field theory and in the advancement of Mathematics at Imperial College London. With his student, Salam made important contributions to the modern theory on neutrinos, neutron stars and black holes, as well as the work on modernising the quantum mechanics and quantum field theory; as a teacher and science promoter, Salam is remembered as a founder and scientific father of mathematical and theoretical physics in Pakistan during his term as the chief scientific advisor to the president.
Salam contributed to the rise of Pakistani physics to the physics community in the world. Until shortly before his death, Salam continued to contribute to physics, to advocate for the development of science in Third-World countries. Abdus Salam was born to Chaudhry Muhammad Hussain and Hajira Hussain, into a Punjabi Muslim family, part of the Ahmadiyya Movement in Islam. In terms of caste-affiliation, they were Jats of Rajput descent from Jhang on his father's side while his mother was a Kakazai from Gurdaspur, his grandfather, Gul Muhammad, was a religious scholar as well as a physician while his father was an education officer in the Department of Education of Punjab State in a poor farming district. Salam early established a reputation throughout the Punjab and at the University of Cambridge for outstanding brilliance and academic achievement. At age 14, Salam scored the highest marks recorded for the matriculation examination at the Punjab University, he won a full scholarship to the Government College University of Punjab State.
Salam was a versatile scholar, interested in Urdu and English literature in which he excelled. But he soon picked up Mathematics as his concentration. Salam's mentor and tutors wanted him to become an English teacher, but Salam decided to stick with Mathematics As a fourth-year student there, he published his work on Srinivasa Ramanujan's problems in mathematics, took his B. A. in Mathematics in 1944. His father wanted him to join Indian Civil Service. In those days, the Indian Civil Service was the highest aspiration for young university graduates and civil servants occupied a respected place in the civil society. Respecting his father's wish, Salam tried for the Indian Railways but did not qualify for the service as he failed the medical optical tests because he had worn spectacles since an early age; the results further concluded that Salam failed a mechanical test required by the railway engineers to gain a commission in Indian Railways, moreover that Salam was too young to compete for the job.
Therefore, Indian Railways rejected Abdus Salam's job application. While in Lahore, Abdus Salam went on to attend the graduate school of Government College University, he received his MA in Mathematics from the Government College University in 1946. That same year, he was awarded a scholarship to St John's College, where he completed a BA degree with Double First-Class Honours in Mathematics and Physics in 1949. In 1950, he received the Smith's Prize from Cambridge University for the most outstanding pre-doctoral contribution to Physics. After finishing his degrees, Fred Hoyle advised Salam to spend another year in the Cavendish Laboratory to do research in experimental physics, but Salam had no patience for carrying out long experiments in the laboratory. Salam returned to Jhang and renewed his scholarship and returned to the United Kingdom to do his doctorate, he obtained a PhD degree in theoretical physics from the Cavendish Laboratory at Cambridge. His doctoral thesis titled "Developments in quantum theory of fields" contained comprehensive and fundamental work in quantum electrodynamics.
By the time it was published in 1951, it had gained him an international reputation and the Adams Prize. During his doctoral studies, his mentors challenged him to solve within one year an intractable problem which had defied such great minds as Dirac and Feynman. Within six months, Salam had found a soluti
The Higgs boson is an elementary particle in the Standard Model of particle physics, produced by the quantum excitation of the Higgs field, one of the fields in particle physics theory. It is named after physicist Peter Higgs, who in 1964, along with five other scientists, proposed the mechanism which suggested the existence of such a particle, its existence was confirmed in 2012 by the ATLAS and CMS collaborations based on collisions in the LHC at CERN. On December 10, 2013, two of the physicists, Peter Higgs and François Englert, were awarded the Nobel Prize in Physics for their theoretical predictions. Although Higgs's name has come to be associated with this theory, several researchers between about 1960 and 1972 independently developed different parts of it. In mainstream media the Higgs boson has been called the "God particle", from a 1993 book on the topic, although the nickname is disliked by many physicists, including Higgs himself, who regard it as sensationalism. Physicists explain the properties of forces between elementary particles in terms of the Standard Model – a accepted framework for understanding everything in the known universe, other than gravity.
In this model, the fundamental forces in nature arise from properties of our universe called gauge invariance and symmetries. The forces are transmitted by particles known as gauge bosons. In the Standard Model, the Higgs particle is a boson with spin zero, no electric charge and no colour charge, it is very unstable, decaying into other particles immediately. The Higgs field is a scalar field, with two neutral and two electrically charged components that form a complex doublet of the weak isospin SU symmetry; the Higgs field has a "Mexican hat-shaped" potential. In its ground state, this causes the field to have a nonzero value everywhere, as a result, below a high energy it breaks the weak isospin symmetry of the electroweak interaction; when this happens, three components of the Higgs field are "absorbed" by the SU and U gauge bosons to become the longitudinal components of the now-massive W and Z bosons of the weak force. The remaining electrically neutral component either manifests as a Higgs particle, or may couple separately to other particles known as fermions, causing these to acquire mass as well.
Field theories had been used with great success in understanding the electromagnetic field and the strong force, but by around 1960 all attempts to create a gauge invariant theory for the weak force had failed, with gauge theories thereby starting to fall into disrepute as a result. The problem was that the symmetry requirements in gauge theory predicted that both electromagnetism's gauge boson and the weak force's gauge bosons should have zero mass. Although the photon is indeed massless, experiments show; this meant that either gauge invariance was an incorrect approach, or something else – unknown – was giving these particles their mass, but all attempts to suggest a theory able to solve this problem just seemed to create new theoretical issues. In the late 1950s, physicists had "no idea" how to resolve these issues, which were significant obstacles to developing a full-fledged theory for particle physics. By the early 1960s, physicists had realised that a given symmetry law might not always be followed under certain conditions, at least in some areas of physics.
This was recognised in the late 1950s by Yoichiro Nambu. Symmetry breaking can lead to unexpected results. In 1962 physicist Philip Anderson – an expert in superconductivity – wrote a paper that considered symmetry breaking in particle physics, suggested that symmetry breaking might be the missing piece needed to solve the problems of gauge invariance in particle physics. If electroweak symmetry was somehow being broken, it might explain why electromagnetism's boson is massless, yet the weak force bosons have mass, solve the problems. Shortly afterwards, in 1963, this was shown to be theoretically possible, at least for some limited cases. Following the 1962 and 1963 papers, three groups of researchers independently published the 1964 PRL symmetry breaking papers with similar conclusions: that the conditions for electroweak symmetry would be "broken" if an unusual type of field existed throughout the universe, indeed, some fundamental particles would acquire mass; the field required for this to happen became known as the Higgs field and the mechanism by which it led to symmetry breaking, known as the Higgs mechanism.
A key feature of the necessary field is that it would take less energy for the field to have a non-zero value than a zero value, unlike all other known fields, the Higgs field has a non-zero value everywhere. It was the first proposal capable of showing how the weak force gauge bosons could have mass despite their governing symmetry, within a gauge invariant theory. Although these ideas did not gain much initial support or attention, by 1972 they had been developed into a comprehensive theory and proved capable of giving "sensible" results that described particles known at the time, which, with exceptional accuracy, predicted several other particles discovered during the following years. During the 1970s these theories became the Standard Mod