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Weinberg Angle
The weak mixing angle or Weinberg angle is a parameter in the Weinberg– Salam theory of the electroweak interaction, part of the Standard Model of particle physics, and is usually denoted as . It is the angle by which spontaneous symmetry breaking rotates the original and vector boson plane, producing as a result the boson, and the photon. Its measured value is slightly below 30°, but also varies, very slightly increasing, depending on how high the relative momentum of the particles involved in the interaction is that the angle is used for. Details The algebraic formula for the combination of the and vector bosons (i.e. 'mixing') that simultaneously produces the massive boson and the massless photon () is expressed by the formula : \begin \gamma \\ Z^0 \end = \begin \cos \theta_\text & \sin \theta_\text \\ -\sin \theta_\text & \cos \theta_\text \end \begin B^0 \\ W^0 \end . The ''weak mixing angle'' also gives the relationship between the masses of the W an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weinberg Angle (relation Between Coupling Constants)
The weak mixing angle or Weinberg angle is a parameter in the Weinberg– Salam theory of the electroweak interaction, part of the Standard Model of particle physics, and is usually denoted as . It is the angle by which spontaneous symmetry breaking rotates the original and vector boson plane, producing as a result the boson, and the photon. Its measured value is slightly below 30°, but also varies, very slightly increasing, depending on how high the relative momentum of the particles involved in the interaction is that the angle is used for. Details The algebraic formula for the combination of the and vector bosons (i.e. 'mixing') that simultaneously produces the massive boson and the massless photon () is expressed by the formula : \begin \gamma \\ Z^0 \end = \begin \cos \theta_\text & \sin \theta_\text \\ -\sin \theta_\text & \cos \theta_\text \end \begin B^0 \\ W^0 \end . The ''weak mixing angle'' also gives the relationship between the masses of the W an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Momentum Transfer
In particle physics, wave mechanics and optics, momentum transfer is the amount of momentum that one particle gives to another particle. It is also called the scattering vector as it describes the transfer of wavevector in wave mechanics. In the simplest example of scattering of two colliding particles with initial momenta \vec_,\vec_, resulting in final momenta \vec_,\vec_, the momentum transfer is given by : \vec q = \vec_ - \vec_ = \vec_ - \vec_ where the last identity expresses momentum conservation. Momentum transfer is an important quantity because \Delta x = \hbar / , q, is a better measure for the typical distance resolution of the reaction than the momenta themselves. Wave mechanics and optics A wave has a momentum p = \hbar k and is a vectorial quantity. The difference of the momentum of the scattered wave to the incident wave is called ''momentum transfer''. The wave number k is the absolute of the wave vector k = p / \hbar and is related to the wavelength k = 2\ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle
In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two rays lie in the plane (geometry), plane that contains the rays. Angles are also formed by the intersection of two planes. These are called dihedral angles. Two intersecting curves may also define an angle, which is the angle of the rays lying tangent to the respective curves at their point of intersection. ''Angle'' is also used to designate the measurement, measure of an angle or of a Rotation (mathematics), rotation. This measure is the ratio of the length of a arc (geometry), circular arc to its radius. In the case of a geometric angle, the arc is centered at the vertex and delimited by the sides. In the case of a rotation, the arc is centered at the center of the rotation and delimited by any other point and its image by the rotation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroweak Theory
In particle physics, the electroweak interaction or electroweak force is the unified description of two of the four known fundamental interactions of nature: electromagnetism and the weak interaction. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 246 GeV,The particular number 246 GeV is taken to be the vacuum expectation value v = (G_\text \sqrt)^ of the Higgs field (where G_\text is the Fermi coupling constant). they would merge into a single force. Thus, if the temperature is high enough – approximately 1015 K – then the electromagnetic force and weak force merge into a combined electroweak force. During the quark epoch (shortly after the Big Bang), the electroweak force split into the electromagnetic and weak force. It is thought that the required temperature of 1015 K has not been seen widely throughout the univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Jefferson National Accelerator Facility
Thomas Jefferson National Accelerator Facility (TJNAF), commonly called Jefferson Lab or JLab, is a US National Laboratory located in Newport News, Virginia. Its stated mission is "to provide forefront scientific facilities, opportunities and leadership essential for discovering the fundamental structure of nuclear matter; to partner in industry to apply its advanced technology; and to serve the nation and its communities through education and public outreach." Since June 1, 2006, it has been operated by Jefferson Science Associates, LLC, a limited liability company created by Southeastern Universities Research Association and PAE Applied Technologies. Until 1996 it was known as the Continuous Electron Beam Accelerator Facility (CEBAF); commonly, this name is still used for the main accelerator. Founded in 1984, Jefferson Lab employs more than 750 people, and more than 2,000 scientists from around the world have conducted research using the facility. History The facility ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Department Of Energy
A Ministry of Energy or Department of Energy is a government department in some countries that typically oversees the production of fuel and electricity; in the United States, however, it manages nuclear weapons development and conducts energy-related research and development. The person in charge of such a department is usually known as a Minister of Energy or Minister for Energy. * Ministry of Energy and Water (Afghanistan) * Ministry of Energy and Mining (Algeria) * Ministry of Energy Infrastructures and Natural Resources (Armenia) * Australia : ** Department of Climate Change and Energy Efficiency (superseded 2013) ** Department of the Environment and Energy (from 2016) * Ministry of Energy (Azerbaijan) * Ministry of Energy, Science & Technology and Public Utilities (Belize) * Ministry of Mines and Energy (Brazil) * Ministry of Energy (Brunei) * Ministry of Economy, Energy and Tourism (Bulgaria) * Burundi Ministry of Energy and Mines * Ministry of Mines and Energy (Cambodia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford Linear Accelerator
SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Department of Energy Office of Science and located in Menlo Park, California. It is the site of the Stanford Linear Accelerator, a 3.2 kilometer (2-mile) linear accelerator constructed in 1966 and shut down in the 2000s, that could accelerate electrons to energies of 50 GeV. Today SLAC research centers on a broad program in atomic and solid-state physics, chemistry, biology, and medicine using X-rays from synchrotron radiation and a free-electron laser as well as experimental and theoretical research in elementary particle physics, astroparticle physics, and cosmology. History Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on of Stanford University-owned land on Sand Hill Road in Menlo Park, Cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considered among the most prestigious universities in the world. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost of Stanford Frederick Terman inspired and supported faculty and graduates' entrepreneu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Data Group
The Particle Data Group (or PDG) is an international collaboration of particle physicists that compiles and reanalyzes published results related to the properties of particles and fundamental interactions. It also publishes reviews of theoretical results that are phenomenologically relevant, including those in related fields such as cosmology. The PDG currently publishes the ''Review of Particle Physics'' and its pocket version, the ''Particle Physics Booklet'', which are printed biennially as books, and updated annually via the World Wide Web. In previous years, the PDG has published the ''Pocket Diary for Physicists'', a calendar with the dates of key international conferences and contact information of major high energy physics institutions, which is now discontinued. PDG also further maintains the standard numbering scheme for particles in event generators, in association with the event generator authors. ''Review of Particle Physics'' The ''Review of Particle Physics'' (former ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Institute Of Standards And Technology
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical science laboratory programs that include nanoscale science and technology, engineering, information technology, neutron research, material measurement, and physical measurement. From 1901 to 1988, the agency was named the National Bureau of Standards. History Background The Articles of Confederation, ratified by the colonies in 1781, provided: The United States in Congress assembled shall also have the sole and exclusive right and power of regulating the alloy and value of coin struck by their own authority, or by that of the respective states—fixing the standards of weights and measures throughout the United States. Article 1, section 8, of the Constitution of the United States, ratified in 1789, granted these powers to the new Congr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LHCb
The LHCb (Large Hadron Collider beauty) experiment is one of eight particle physics detector experiments collecting data at the Large Hadron Collider at CERN. LHCb is a specialized b-physics experiment, designed primarily to measure the parameters of CP violation in the interactions of b-hadrons (heavy particles containing a bottom quark). Such studies can help to explain the matter-antimatter asymmetry of the Universe. The detector is also able to perform measurements of production cross sections, exotic hadron spectroscopy, charm physics and electroweak physics in the forward region. The LHCb collaboration, who built, operate and analyse data from the experiment, is composed of approximately 1260 people from 74 scientific institutes, representing 16 countries. Chris Parkes succeeded on July 1, 2020 as spokesperson for the collaboration to Giovanni Passaleva (spokesperson 2017-2020). The experiment is located at point 8 on the LHC tunnel close to Ferney-Voltaire, France just o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Møller Scattering
Møller scattering is the name given to electron-electron scattering in quantum field theory, named after the Danish physicist Christian Møller. The electron interaction that is idealized in Møller scattering forms the theoretical basis of many familiar phenomena such as the repulsion of electrons in the helium atom. While formerly many particle colliders were designed specifically for electron-electron collisions, more recently electron-positron colliders have become more common. Nevertheless, Møller scattering remains a paradigmatic process within the theory of particle interactions. We can express this process in the usual notation, often used in particle physics: e^ e^ \longrightarrow e^ e^, In quantum electrodynamics, there are two tree-level Feynman diagrams describing the process: a t-channel diagram in which the electrons exchange a photon and a similar u-channel diagram. Crossing symmetry, one of the tricks often used to evaluate Feynman diagrams, in this case imp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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