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WA70 Experiment
The WA70 experiment was a collaboration between the Universities of Geneva, Glasgow, Liverpool, Milan and Neuchatel using the facilities of the OMEGA spectrometer at CERN. The purpose of the experiment was to study direct photons produced in proton-proton and proton-pion collisions within a fixed target of liquid hydrogen at the CERN SPS. The experiment was proposed on 6 August 1980 and formally approved on 22 October 1981. Preliminary data was taken in 1983 with physics runs in 1984, 1985 and 1986. A novel feature of the experiment was a liquid scintillator calorimeter, which was built in quadrants and designed to measure the energy of direct photons and other particles produced by the collisions. This was situated downstream of the liquid hydrogen target. Results were presented at scientific conferences and published in scientific journals. The measured cross section for direct photon production was in agreement with predictions from perturbative QCD. The spokesperson fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Hydrogen
Liquid hydrogen (LH2 or LH2) is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form. To exist as a liquid, H2 must be cooled below its critical point of 33 K. However, for it to be in a fully liquid state at atmospheric pressure, H2 needs to be cooled to .IPTS-1968 iupac.org, accessed 2020-01-01 A common method of obtaining liquid hydrogen involves a compressor resembling a jet engine in both appearance and principle. Liquid hydrogen is typically used as a concentrated form of . Storing it as liquid takes less space than storing it as a gas at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
INSPIRE-HEP
INSPIRE-HEP is an open access digital library for the field of high energy physics (HEP). It is the successor of the Stanford Physics Information Retrieval System (SPIRES) database, the main literature database for high energy physics since the 1970s. History SPIRES was (in addition to the CERN Document Server (CDS), arXiv and parts of Astrophysics Data System) one of the main Particle Information Resources. A survey conducted in 2007 found that SPIRES database users wanted the portal to provide more services than the, at that time, already 30-year-old system could provide. On the second annual Summit of Information Specialists in Particle Physics and Astrophysics in May 2008, the physics laboratories CERN, DESY, SLAC and Fermilab therefore announced that they would work together to create a new Scientific Information System for high energy physics called INSPIRE. It interacts with other HEP service providers like arXiv.org, Particle Data Group, NASA's Astrophysics Data System. and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Directors General Of CERN
CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ... directors general typically serve 5 year terms beginning on January 1. List {{DEFAULTSORT:Directors General Of Cern CERN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabiola Gianotti
Fabiola Gianotti (; born 29 October 1960) is an Italian experimental particle physicist who is the current and first woman Director-General at CERN (European Organization for Nuclear Research) in Switzerland. Her first mandate began on 1 January 2016 and ran for a period of five years. At its 195th Session in 2019, the CERN Council selected Gianotti for a second term as Director-General. Her second five-year term began on 1 January 2021 and goes on until 2025. This is the first time in CERN's history that a Director-General has been appointed for a full second term. Early life and education From an early age, Gianotti was interested in nature and the world around her. Her mother, from Sicily, encouraged Gianotti in the fine arts. Her father, an acclaimed geologist from Piedmont, encouraged her early love of learning and encouraged her scientific interests. Gianotti found her passion for scientific research after reading a biography on Marie Curie. Previously, she had studie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Chromodynamics
In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks mediated by gluons. Quarks are fundamental particles that make up composite hadrons such as the proton, neutron and pion. QCD is a type of quantum field theory called a non-abelian gauge theory, with symmetry group SU(3). The QCD analog of electric charge is a property called ''color''. Gluons are the force carriers of the theory, just as photons are for the electromagnetic force in quantum electrodynamics. The theory is an important part of the Standard Model of particle physics. A large body of experimental evidence for QCD has been gathered over the years. QCD exhibits three salient properties: * Color confinement. Due to the force between two color charges remaining constant as they are separated, the energy grows until a quark–antiquark pair is spontaneously produced, turning the initial hadron into a pair of hadrons instead of isolating a color charge. Although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross Section (physics)
In physics, the cross section is a measure of the probability that a specific process will take place when some kind of radiant excitation (e.g. a particle beam, sound wave, light, or an X-ray) intersects a localized phenomenon (e.g. a particle or density fluctuation). For example, the Rutherford cross-section is a measure of probability that an alpha particle will be deflected by a given angle during an interaction with an atomic nucleus. Cross section is typically denoted ( sigma) and is expressed in units of area, more specifically in barns. In a way, it can be thought of as the size of the object that the excitation must hit in order for the process to occur, but more exactly, it is a parameter of a stochastic process. In classical physics, this probability often converges to a deterministic proportion of excitation energy involved in the process, so that, for example, with light scattering off of a particle, the cross section specifies the amount of optical power scattere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calorimeter (particle Physics)
In particle physics, a calorimeter is an experimental apparatus that measures the energy of particles. Most particles enter the calorimeter and initiate a particle shower and the particles' energy is deposited in the calorimeter, collected, and measured. The energy may be measured in its entirety, requiring total containment of the particle shower, or it may be sampled. Typically, calorimeters are segmented transversely to provide information about the direction of the particle or particles, as well as the energy deposited, and longitudinal segmentation can provide information about the identity of the particle based on the shape of the shower as it develops. Calorimetry design is an active area of research in particle physics. Types of calorimeters Electromagnetic versus hadronic An electromagnetic calorimeter is one specifically designed to measure the energy of particles that interact primarily via the electromagnetic interaction, while a hadronic calorimeter is one designed t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super Proton Synchrotron
The Super Proton Synchrotron (SPS) is a particle accelerator of the synchrotron type at CERN. It is housed in a circular tunnel, in circumference, straddling the border of France and Switzerland near Geneva, Switzerland. History The SPS was designed by a team led by John Adams, director-general of what was then known as Laboratory II. Originally specified as a 300 GeV accelerator, the SPS was actually built to be capable of 400 GeV, an operating energy it achieved on the official commissioning date of 17 June 1976. However, by that time, this energy had been exceeded by Fermilab, which reached an energy of 500 GeV on 14 May of that year. The SPS has been used to accelerate protons and antiprotons, electrons and positrons (for use as the injector for the Large Electron–Positron Collider (LEP)), and heavy ions. From 1981 to 1991, the SPS operated as a hadron (more precisely, proton–antiproton) collider (as such it was called SpS), when its beams provided the data ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pion
In particle physics, a pion (or a pi meson, denoted with the Greek 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 decay into muons and muon neutrinos, while neutral pions generally decay into gamma rays. The exchange of virtual pions, along with vector, rho and omega mesons, provides an explanation for the 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 matter–antimatter annihilation events. All types of pions are also produced in natural processes wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Geneva
The University of Geneva (French: ''Université de Genève'') is a public research university located in Geneva, Switzerland. It was founded in 1559 by John Calvin as a theological seminary. It remained focused on theology until the 17th century, when it became a center for enlightenment scholarship. Today, it is the third largest university in Switzerland by number of students. In 1873, it dropped its religious affiliations and became officially secular. In 2009, the University of Geneva celebrated the 450th anniversary of its founding. Almost 40% of the students come from foreign countries. The university holds and actively pursues teaching, research, and community service as its primary objectives. In 2016, it was ranked 53rd worldwide by the Shanghai Academic Ranking of World Universities, 89th by the QS World University Rankings, and 131st in the Times Higher Education World University Ranking. UNIGE is a member of the League of European Research Universities (includi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proton
A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ratio). Protons and neutrons, each with masses of approximately one atomic mass unit, are jointly referred to as "nucleons" (particles present in atomic nuclei). One or more protons are present in the nucleus of every atom. They provide the attractive electrostatic central force which binds the atomic electrons. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number (represented by the symbol ''Z''). Since each element has a unique number of protons, each element has its own unique atomic number, which determines the number of atomic electrons and consequently the chemical characteristics of the element. The word ''proton'' is Greek for "first", and this name was given to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
