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Tetraquarks
In particle physics, a tetraquark is an exotic meson composed of four valence quarks. A tetraquark state has long been suspected to be allowed by quantum chromodynamics, the modern theory of strong interactions. A tetraquark state is an example of an exotic hadron that lies outside the conventional quark model classification. A number of different types of tetraquark have been observed. History and discoveries Several tetraquark candidates have been reported by particle physics experiments in the 21st century. The quark contents of these states are almost all qQ, where q represents a light (up quark, up, down quark, down or strange quark, strange) quark, Q represents a heavy (charm quark, charm or bottom quark, bottom) quark, and antiquarks are denoted with an overline. The existence and stability of tetraquark states with the qq (or QQ) have been discussed by theoretical physicists for a long time, however these are yet to be reported by experiments. ;Timeline In 2003, a par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exotic Meson
In particle physics, exotic mesons are mesons that have quantum numbers not possible in the quark model; some proposals for non-standard quark model mesons could be: ;glueballs or gluonium: Glueballs have no valence quarks at all. ;tetraquarks: Tetraquarks have two valence quark–antiquark pairs. ;hybrid mesons: Hybrid mesons contain a valence quark–antiquark pair and one or more gluons. All exotic mesons are classed as mesons because they are hadrons and carry zero baryon number. Of these, glueballs must be flavor singlets – that is, must have zero isospin, strangeness, charm, bottomness, and topness. Like all particle states, exotic mesons are specified by the quantum numbers which label representations of the Poincaré symmetry, q.e., by the mass (enclosed in parentheses), and by , where is the angular momentum, is the intrinsic parity, and is the charge conjugation parity; One also often specifies the isospin of the meson. Typically, every quark model meson c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Physics
Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, 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 combinations of protons and neutrons is called nuclear physics. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and bosons (force-carrying particles). There are three Generation (particle physics), generations of fermions, although ordinary matter is made only from the first fermion generation. The first generation consists of Up quark, up and down quarks which form protons and neutrons, and electrons and electron neutrinos. The three fundamental interactions known to be mediated by bosons are electromagnetism, the weak interaction, and the strong interaction. Quark, Quarks cannot exist on their own but form hadrons. Hadrons that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics World
''Physics World'' is the membership magazine of the Institute of Physics, one of the largest physical societies in the world. It is an international monthly magazine covering all areas of physics, pure and applied, and is aimed at physicists in research, industry, physics outreach, and education worldwide. Overview The magazine was launched in 1988 by IOP Publishing Ltd, under the founding editorship of Philip Campbell. The magazine is made available free of cost to members of the Institute of Physics, who can access a digital edition of the magazine; selected articles can be read by anyone for free online. It was redesigned in September 2005 and has an audited circulation of just under 35000. The current editor is Matin Durrani. Others on the team are Michael Banks (news editor) and Tushna Commissariat and Sarah Teah (features editors). Hamish Johnston, Margaret Harris and Tami Freeman are online editors. Alongside the print and online magazine, Physics World produces film ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resonance (particle Physics)
In particle physics, a resonance is the peak located around a certain energy found in differential cross sections of scattering experiments. These peaks are associated with subatomic particles, which include a variety of bosons, quarks and hadrons (such as nucleons, delta baryons or upsilon mesons) and their excitations. In common usage, "resonance" only describes particles with very short lifetimes, mostly high-energy hadrons existing for or less. It is also used to describe particles in intermediate steps of a decay, so-called virtual particles. The width of the resonance (''Γ'') is related to the mean lifetime (''τ'') of the particle (or its excited state) by the relation :\Gamma=\frac where =\frac and ''h'' is the Planck constant. Thus, the lifetime of a particle is the direct inverse of the particle's resonance width. For example, the charged pion has the second-longest lifetime of any meson, at . Therefore, its resonance width is very small, about or about 6.11 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bottomonium
In particle physics, quarkonium (from quark and -onium, pl. quarkonia) is a flavorless meson whose constituents are a heavy quark and its own antiquark, making it both a neutral particle and its own antiparticle. The name "quarkonium" is analogous to positronium, the bound state of electron and anti-electron. The particles are short-lived due to matter-antimatter annihilation. Light quarks Light quarks ( up, down, and strange) are much less massive than the heavier quarks, and so the physical states actually seen in experiments ( η, η′, and π0 mesons) are quantum mechanical mixtures of the light quark states. The much larger mass differences between the charm and bottom quarks and the lighter quarks results in states that are well defined in terms of a quark–antiquark pair of a given flavor. Heavy quarks Quarkonia, bound state of ''charmonium'' (c\bar) and ''bottomonium'' (b\bar) pairs, are crucial probes for studying the deconfined quark-gluon plasma created in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upsilon Meson
The Upsilon meson () is a quarkonium state (i.e. flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, headed by Leon Lederman, at Fermilab in 1977, and was the first particle containing a bottom quark to be discovered because it is the lightest that can be produced without additional massive particles. It has a lifetime of and a mass about in the ground state. File:Quark structure bottomonium.svg, Quark structure of the Upsilon meson See also * Oops-Leon, an erroneously-claimed discovery of a similar particle at a lower mass in 1976. * The particle is the analogous state made from strange quarks. * The particle is the analogous state made from charm quarks. * List of mesons : ''This list is of all known and predicted scalar, pseudoscalar and vector mesons. See list of particles for a more detailed list of particles found in particle physics.'' This article contains a list of mesons, unstable subatomic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaid-i-Azam University
Quaid-i-Azam University (QAU), founded as the University of Islamabad, is a public research university in Islamabad, Pakistan. Founded as the University of Islamabad in 1967, it was initially dedicated to postgraduate study, but later expanded to an interdisciplinary university offering both undergraduate and postgraduate education. The university became known by its current name in 1976. Overview , QAU has grown into the largest university in Islamabad with a total enrollment exceeding 13,000 students. The university is on a 1700 acre (6.9 km2) campus on the foothills of the Margalla. Divided into four faculties and nine affiliated research institutes, QAU is among Pakistan's largest and highest-ranked universities. The university has interacted with international institutions, including the United Nations, University of Tokyo and the ICTP. It counts several public figures and intellectuals among its current and former faculty, researchers, or alumni since its establishme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DESY
DESY, short for Deutsches Elektronen-Synchrotron (English: ''German Electron Synchrotron''), is a national research centre for fundamental science located in Hamburg and Zeuthen near Berlin in Germany. It operates particle accelerators used to investigate the structure, dynamics and function of matter, and conducts a broad spectrum of interdisciplinary scientific research in four main areas: particle physics, particle and high energy physics; photon science; astroparticle physics; and the development, construction and operation of particle accelerators. Its name refers to its first project, an electron synchrotron. DESY is publicly financed by the Federal Republic of Germany and the Federal States of Hamburg and Brandenburg and is a member of the Helmholtz Association. Functions and mission DESY's function is to conduct fundamental research for solely civil and peaceful purposes. It specialises in particle accelerator development, construction and operation, particle physics, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Universe Today
Universe Today (U.T.) is a North American-based non-commercial space and astronomy news website founded by Fraser Cain. The domain was registered on December 30, 1998, and the website went live in March 1999. ''Universe Today'' assumed its current form on July 24, 2003, featuring astronomy news and other space-related content. In early September 2005, the website’s forum section merged with '' Bad Astronomy'' to create a combined site with the BAUT forum. During April 2011, the Association of British Science Writers noted that ''Universe Today'' decided not to make preparations for reporting on embargoed stories until they are public knowledge. Emily Lakdawalla said that she relies on ''Universe Today'' and '' Bad Astronomy'' to "give ... an independent look at big news stories". Publications ''Universe Today'' has published two books, which are available both as e-books and on physical media: * * See also * '' Astronomy Cast'' * ''Space.com Space.com is an on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y(4140)
The Y(4140) particle is an electrically neutral exotic hadron candidate that is about 4.4 times heavier than the proton. It was observed at Fermilab and announced on 17 March 2009. This particle is extremely rare and was detected in only 20 of billions of collisions. Since it decays into J/ψ and φ mesons, it has been suggested that this particle is composed of charm quarks and charm antiquarks, possibly even a four quark combination. The existence of the particle has been confirmed by members of the CMS collaboration at the Large Hadron Collider on November 14, 2012 and by the DØ experiment at the Tevatron on September 25, 2013. The Belle experiment has searched for this particle but found no evidence for its existence. The LHCb experiment observes a peak at the same position in the J/ψΦ invariant mass, but it is best described as a Ds±Ds∗∓ cusp, and is much broader than the previous measurements of the Y(4140). The Particle Data Group has renamed Y(4140) to follow nam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Review Letters
''Physical Review Letters'' (''PRL''), established in 1958, is a peer-reviewed, scientific journal that is published 52 times per year by the American Physical Society. The journal is considered one of the most prestigious in the field of physics. Over a quarter of Physics Nobel Prize-winning papers between 1995 and 2017 were published in it. ''PRL'' is published both online and as a print journal. Its focus is on short articles ("letters") intended for quick publication. The Lead Editor is Hugues Chaté. The Managing Editor is Robert Garisto. History The journal was created in 1958. Samuel Goudsmit, who was then the editor of '' Physical Review'', the American Physical Society's flagship journal, organized and published ''Letters to the Editor of Physical Review'' into a new standalone journal'','' which became ''Physical Review Letters''. It was the first journal intended for the rapid publication of short articles, a format that eventually became popular in many other fiel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y(4660)
Y, or y, is the twenty-fifth and penultimate letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. According to some authorities, it is the sixth (or seventh if including W) vowel letter of the English alphabet. Its name in English is ''wye'' (pronounced ), plural ''wyes''. In the English writing system, it mostly represents a vowel and seldom a consonant, and in other orthographies it may represent a vowel or a consonant. Name In Latin, Y was named ''I graeca'' ("Greek I"), since the classical Greek sound , similar to modern German ''ü'' or French ''u'', was not a native sound for Latin speakers, and the letter was initially only used to spell foreign words. This history has led to the standard modern names of the letter in Romance languages – ''i grego'' in Galician, ''i grega'' in Catalan, ''i grec'' in French and Romanian, and ''i greca'' in Italian – all meaning "Greek I". The n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
