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NA31 Experiment
NA31 is a CERN experiment which was proposed in 1982 as a measurement of , η00 /η+-, 2 by the CERN-Edinburgh-Mainz-Pisa-Siegen collaboration. It took data between 1986 and 1989, using a proton beam from the SPS through the K4 neutral beam-line. Its aim was to experimentally prove direct CP-violation. CP violation While charge symmetry and parity symmetry are both violated for any transformation under the weak interaction, the CP violation is known only to appear in particular phenomena - kaon and B-meson decays - under the weak interaction. CP-violation was first theoretically developed for the Standard Model by Kobayashi and Maskawa in 1973 when they introduced a third generation of quark (bottom and top) and thus extended the Cabibbo matrix to the 3x3 CKM matrix, parameterizing the couplings between quark-mass eigenstates and the charge weak gauge bosons. CP violation then appears through the presence of complex parameters in this matrix. Determined from the relati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pion
In particle physics, a pion (, ) or pi meson, denoted with the Greek alphabet, Greek letter pi (letter), pi (), is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more generally, the lightest hadrons. They are unstable, with the charged pions and decaying after a mean lifetime of 26.033 nanoseconds ( seconds), and the neutral pion decaying after a much shorter lifetime of 85 attoseconds ( seconds). Charged pions most often particle decay, decay into muons and muon neutrinos, while neutral pions generally decay into gamma rays. The exchange of virtual particle, virtual pions, along with vector meson, vector, rho meson, rho and omega mesons, provides an explanation for the nuclear force, residual strong force between nucleons. Pions are not produced in radioactive decay, but commonly are in high-energy collisions between hadrons. Pions also result from some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid
Liquid is a state of matter with a definite volume but no fixed shape. Liquids adapt to the shape of their container and are nearly incompressible, maintaining their volume even under pressure. The density of a liquid is usually close to that of a solid, and much higher than that of a gas. Therefore, liquid and solid are classified as condensed matter. Meanwhile, since both liquids and gases can flow, they are categorized as fluids. A liquid is composed of atoms or molecules held together by intermolecular bonds of intermediate strength. These forces allow the particles to move around one another while remaining closely packed. In contrast, solids have particles that are tightly bound by strong intermolecular forces, limiting their movement to small vibrations in fixed positions. Gases, on the other hand, consist of widely spaced, freely moving particles with only weak intermolecular forces. As temperature increases, the molecules in a liquid vibrate more intensely, causi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Charge
Electric charge (symbol ''q'', sometimes ''Q'') is a physical property of matter that causes it to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative''. Like charges repel each other and unlike charges attract each other. An object with no net charge is referred to as neutral particle, electrically neutral. Early knowledge of how charged substances interact is now called classical electrodynamics, and is still accurate for problems that do not require consideration of quantum mechanics, quantum effects. In an isolated system, the total charge stays the same - the amount of positive charge minus the amount of negative charge does not change over time. Electric charge is carried by subatomic particles. In ordinary matter, negative charge is carried by electrons, and positive charge is carried by the protons in the atomic nucleus, nuclei of atoms. If there are more electrons than protons in a piece of matter, it will have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Space
The phase space of a physical system is the set of all possible physical states of the system when described by a given parameterization. Each possible state corresponds uniquely to a point in the phase space. For mechanical systems, the phase space usually consists of all possible values of the position and momentum parameters. It is the direct product of direct space and reciprocal space. The concept of phase space was developed in the late 19th century by Ludwig Boltzmann, Henri Poincaré, and Josiah Willard Gibbs. Principles In a phase space, every degree of freedom or parameter of the system is represented as an axis of a multidimensional space; a one-dimensional system is called a phase line, while a two-dimensional system is called a phase plane. For every possible state of the system or allowed combination of values of the system's parameters, a point is included in the multidimensional space. The system's evolving state over time traces a path (a phase-spac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interaction Point
In particle physics, an interaction point (IP) is the place where particles collide in an accelerator experiment. The ''nominal'' interaction point is the design position, which may differ from the ''real'' or ''physics'' interaction point, where the particles actually collide. A related, but distinct, concept is the ''primary vertex'': the reconstructed location of an individual particle collision. For fixed target experiments, the interaction point is the point where beam and target interact. For colliders, it is the place where the beams interact. Experiments (detectors) at particle accelerators are built around the nominal interaction points of the accelerators. The whole region around the interaction point (the experimental hall) is called an interaction region. Particle colliders such as LEP, HERA, RHIC, Tevatron and LHC The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It was built by the European Organization for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy
Energy () is the physical quantity, quantitative physical property, property that is transferred to a physical body, body or to a physical system, recognizable in the performance of Work (thermodynamics), work and in the form of heat and light. Energy is a Conservation law, conserved quantity—the law of conservation of energy states that energy can be Energy transformation, converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J). Forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a Classical field theory, field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, the internal energy contained within a thermodynamic system, and rest energy associated with an object's rest mass. These are not mutual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calorimetry
In chemistry and thermodynamics, calorimetry () is the science or act of measuring changes in '' state variables'' of a body for the purpose of deriving the heat transfer associated with changes of its state due, for example, to chemical reactions, physical changes, or phase transitions under specified constraints. Calorimetry is performed with a calorimeter. Scottish physician and scientist Joseph Black, who was the first to recognize the distinction between heat and temperature, is said to be the founder of the science of calorimetry. Indirect calorimetry calculates heat that living organisms produce by measuring either their production of carbon dioxide and nitrogen waste (frequently ammonia in aquatic organisms, or urea in terrestrial ones), or from their consumption of oxygen. Lavoisier noted in 1780 that heat production can be predicted from oxygen consumption this way, using multiple regression. The dynamic energy budget theory explains why this procedure is corre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wire Chambers
Overhead power cabling. The conductor consists of seven strands of steel (centre, high tensile strength), surrounded by four outer layers of aluminium (high conductivity). Sample diameter 40 mm A wire is a flexible, round bar of metal. Wires are commonly formed by drawing the metal through a hole in a die or draw plate. Wire gauges come in various standard sizes, as expressed in terms of a gauge number or cross-sectional area. Wires are used to bear mechanical loads, often in the form of wire rope. In electricity and telecommunications signals, ''wire'' can refer to electrical cable, which can contain a solid core of a single wire or separate strands in stranded or braided forms. Usually cylindrical in geometry, wire can also be made in square, hexagonal, flattened rectangular, or other cross-sections, either for decorative purposes, or for technical purposes such as high-efficiency voice coils in loudspeakers. Edge-wound coil springs, such as the Slinky toy, are made of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Layout Of The NA31 Experiment
In general terms, a layout is a structured arrangement of items within certain limits, or a plan for such arrangement. Specifically, layout may refer to: * Page layout, the arrangement of visual elements on a page ** Comprehensive layout (comp), a proposed page layout presented by a designer to their client * Layout (computing), the process of calculating the position of objects in space * Layout engine, another name for web browser engine, the core software that displays content in a web browser * Automobile layout, a description of the locations of the engine and drive wheels on a vehicle * Integrated circuit layout, the representation of an integrated circuit in geometric shapes * Keyboard layout, an arrangement of the keys on a typographic keyboard * Model railroad layout, a diorama with tracks for operating scaled-down trains *Layout (dominoes), the tableau in a domino game * Layout or marking out, the transfer of a design onto a workpiece in manufacturing * Plant layout st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Energy And Particle Physics Prize
The High Energy and Particle Physics Prize, established in 1989, is awarded every two years by the European Physical Society (EPS) for an outstanding contribution to high energy and particle physics. Recipients Source: * 1989 Georges Charpak * 1991 Nicola Cabibbo * 1993 Martinus Veltman * 1995 Paul Söding, Bjørn Wiik, , Sau Lan Wu * 1997 Robert Brout, Francois Englert, François Englert, Peter Higgs * 1999 Gerard ’t Hooft * 2001 Donald Hill Perkins, Don Perkins * 2003 David Gross, David Politzer, Frank Wilczek * 2005 and the NA31 Collaboration * 2007 Makoto Kobayashi (physicist), Makoto Kobayashi, Toshihide Maskawa * 2009 The Gargamelle collaboration * 2011 Sheldon Glashow, John Iliopoulos, Luciano Maiani * 2013 The ATLAS experiment, ATLAS and Compact Muon Solenoid, CMS collaborations, Michel Della Negra, Peter Jenni, Tejinder Virdee * 2015 James D. Bjorken, Guido Altarelli, , Lev Lipatov, Giorgio Parisi * 2017 , , * 2019 The Collider Detector at Fermilab, CDF and DØ exper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Physical Society
The European Physical Society (EPS) is a non-profit organisation whose purpose is to promote physics and physicists in Europe through methods such as physics outreach, supporting physicists to engage in the design and implementation of European science policy, and advocating physics research. Formally established in 1968, its membership includes the national physical societies of 42 countries, and some 3200 individual members. The Deutsche Physikalische Gesellschaft, the world's largest and oldest organisation of physicists, is a major member. History In 1966, Gilberto Bernardini, then president of the Italian Physical Society, convened a meeting of 80 European physicists in Pisa to discuss possibly forming a Pan-European Physical Society. There was agreement in such a society existed, but disagreement about its form which led to the establishment of a Steering Committee. They would attempt to determine if a federation of national physical societies or an independent society with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
