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Topic: Muon


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In the News (Fri 22 Mar 19)

  
  muon. The Columbia Encyclopedia, Sixth Edition. 2001-05
However, the muon’s behavior did not conform to that of Yukawa’s meson theory (which actually describes the pion, discovered more than 10 years later), and the muon is now classed as a lepton rather than a meson.
Muons are produced by the weak decay of pions into a muon and a muon antineutrino.
Muons can be substituted for electrons in orbit around the nucleus of an atom; the resulting atom is long-lived enough to exhibit behavior that further supports the close resemblance between the muon and the electron.
www.bartleby.com /65/mu/muon.html   (355 words)

  
 Leptons
The muon is a lepton which decays to form an electron or positron.
The muon is produced in the upper atmosphere by the decay of pions produced by cosmic rays:
Muons make up more than half of the cosmic radiation at sea level, the remainder being mostly electrons, positrons and photons from cascade events.(Richtmyer) The average sea level muon flux is about 1 muon per square centimeter per minute.
hyperphysics.phy-astr.gsu.edu /hbase/particles/lepton.html   (635 words)

  
 Muon Summary
The muon's mass led physicists to believe it was the particle predicted by the Japanese physicist Yukawa Hideki to explain the strong interaction that binds protons and neutrons together in atomic nuclei.
Muons are one of the main components of cosmic radiation at the earth's surface, produced by the decay of ions high in the atmosphere.
Muons do not exist at the levels of energy available in everyday life, but are created in high-energy environments such as those that exist in cosmic ray showers and in particle accelerator reactions.
www.bookrags.com /Muon   (1622 words)

  
 [No title]
Muons provide an alternative to the neutron as a probe of condensed matter and are frequently used in complementary experiments.
Free muons have a mean lifetime of 2.2 µs, decaying into a positron and two neutrinos, with the positron emitted preferentially in the direction of the muon spin, allowing the time evolution of the muon polarisation to be measured by detecting the position of the decay positrons.
In condensed matter, muons are repelled by the nuclei, and thus muons probe magnetic fields in the interstitial regions between the atoms.
www.isis.rl.ac.uk /aboutIsis/whatisaMuon.htm   (478 words)

  
 Muon Radiography, Detecting Nuclear Contraband | Spring 2003 | Los Alamos National Laboratory
Muons, elementary particles that shower down on Earth, hold promise as a sensitive means of detecting nuclear materials being smuggled into the country.
The deflection is also determined by how many nuclei a muon encounters while passing through the material, which is proportional to the number of nuclei per unit volume—the number density.
Los Alamos simulations, validated with small-scale experiments, show that cosmic-ray muons can penetrate the 3-millimeter-thick steel walls of a freight truck to detect a block of nuclear or gamma-ray-shielding material 10 centimeters (4 inches) on a side hidden among other cargo, such as livestock or auto parts.
www.lanl.gov /quarterly/q_spring03/muon_text.shtml   (1631 words)

  
 Muon - Wikipedia, the free encyclopedia
The muon (from the letter mu (μ) used to represent it) is an elementary particle with negative electric charge and a spin of 1/2.
In naturally-produced muons, the very high-energy protons to begin the process are thought to originate from acceleration by electromagnetic fields over long distances between stars or galaxies, in a manner somewhat analogous to the mechanism of proton acceleration used in laboratory particle accelerators.
The muon was the first elementary particle discovered that does not appear in ordinary atoms.
en.wikipedia.org /wiki/Muon   (1191 words)

  
 Muon
According to the Standard Model of particle physics, a muon (also known as a mu meson) is a collective name for two semistable fundamental particles with positive and negative charge.
Muons have a mass that is 207 times greater than the electron (105.6 MeV) and a spin of 1/2.
Both electrons and muons belong to to the same family of fermions (i.e., fundamental particles) called the leptons.
www.ebroadcast.com.au /lookup/encyclopedia/mu/Muons.html   (212 words)

  
 muon@Everything2.com   (Site not responding. Last check: 2007-10-14)
However, when the dust finally settled and the Standard Model was born, the muon retained it's status as fundamental, as the charged lepton in the second generation of elementary particles.
The muon is a member of the class of particles known as 'leptons' and was discovered in 1935 by Carl Anderson and Seth Neddermeyer looking at cosmic rays (the paper was published in 1936).
As it moves to the ground state (the muon atom is created in an excited state) the muon will be giving off x-rays and causing electrons to leave the atom (known as Auger electrons).
everything2.com /index.pl?node=muon   (730 words)

  
 Muon - Uncyclopedia, the content-free encyclopedia
The Muon is a fundamentalist particle created by an experiment between the US Food and Drug Administration and the Manhattan Project.
The muon was re-discovered about a decade later when the Department was looking for a new source of milk, as all the cows were dying out due to a security flaw in their Windows Operating Systems.
Soon, concentrated muon was being shipped to laboratories world-wide, in the hunt for the preservative that would allow it to be drinkable.
www.uncyclopedia.org /wiki/Muon   (473 words)

  
 Muon g-2 Vocabulary and Terms
The muon, electron, and tau are generically referred to as charged leptons, and they have the remarkable property that they are believed to be point particles.
When the muons are injected into the storage ring, their spin axes are in the horizontal plane (in fact they are aligned with their direction of motion).
The north-south poles of the muon magnet are aligned with the spin direction, so themagnetic field will exert a torque which tends to align the spin axis with the direction of the field, just like a compass or bar magnet would align along the field.
www.bnl.gov /bnlweb/pubaf/pr/2001/g-2_glossary.htm   (1104 words)

  
 muon - Search Results - MSN Encarta
discovery of muons, discovery of particle, elementary particles, experimentally known elementary particles (table), leptons, type of lepton
creation of muon neutrinos and antineutrinos, detection of muon neutrinos, discovery of muon neutrinos, experimentally known elementary particles...
The theory scientists favor to explain the problem is that neutrinos from the Sun change on their way to Earth.
ca.encarta.msn.com /muon.html   (97 words)

  
 PmWikiFisica | MuSR / The Muon Fate browse
The initial energy of the muon, of the order of 4 MeV, is huge compared to the typical energies of the electrons with whom it collides (from few eV, for valence shells, to several hundred keV for inner shells in heavy elements.
In this context the positive muon may be regarded as a light isotope of hydrogen, whose complex epithermal chemistry reactions in the host material determine its successive fate.
Muons seldom replace an atom of the host compound: this may be the case when cation vacancies are abundant or when a MU-H exchange takes place, e.g.
www.fis.unipr.it /~derenzi/dispense/pmwiki.php?n=MuSR.TheMuonFate   (530 words)

  
 Muon Lifetime
Muons are produced in the atmosphere in cosmic-ray induced air showers, and because they are quite penetrating they can reach the ground, enter the laboratory through the walls or roof of the building, and be detected with a suitable apparatus.
Basically, when a muon decays inside the volume of the drum, two pulses of light are produced, due first to the muon itself, and then to the electron (or positron) resulting from the decay.
Also, since the muons are relativistic and their crossing time short (difficult to measure accurately), it may be a good idea to artificially lengthen the travel time by a constant amount by introducing an appropriate long delay cable somewhere in the circuit.
class.phys.psu.edu /p559/experiments/html/muonlifetime.html   (959 words)

  
 Muon Identification Overview
Muon reconstruction utilizes the inner tracking, thecalorimeter, and the muon detector elements themselvesto identify muons and determine their energy.
Muon backgrounds in Run I were from cosmic ray muons and combinatorics.For Run II, we have the additional ability to trigger and reconstruct lowerpt muons which hit only the a-layer.
Offline Muon ID The offline muon identification is based on a match between a charged particle detected in the central trackerand a signal in the muon system.
nicadd.niu.edu /~hedin/muonid.html   (2656 words)

  
 Muons
Muons are the most numerous energetic charged particles at sea level.
Muons (and other particles) are generated within a cone-shaped shower, with all particles staying within about 1 degree of the primary particle's path.
This disparity may be primarily due to the impending decays of muons, as the path length exceeds their range.
www.lbl.gov /abc/cosmic/SKliewer/Cosmic_Rays/Muons.htm   (466 words)

  
 Decay of Muon Cosmic Ray
A Muon is an elementary particle in the lepton (particles in which beta decay is the dominant force) family, having a mass 209 times that of the electron, and a negative electric charge.
Muons are also a by-product of the interactions between cosmic rays and nuclei in the atmosphere.
The cross-sectional area of the cloud chamber was relatively small (size of a hand palm) and this restricted the likelihood of viewing a muon particle.
www.angelfire.com /fl2/due/Muons.htm   (1657 words)

  
 Los Alamos muon detector could thwart nuclear smugglers | The Newsbulletin | February 22, 2005
Their technique, muon radiography, is far more sensitive than x-rays, with none of the radiation hazards of x-ray or gamma-ray detectors now in use at U.S. borders.
Muon radiography uses the natural scattering of muons - produced by the decay of cosmic rays showering down on Earth - as a radiographic probe.
Muons strike the Earth from every angle, so the key to a workable detection system is to keep improving the computer algorithms for tomographic reconstruction.
www.lanl.gov /orgs/pa/newsbulletin/2005/02/22/text03.shtml   (830 words)

  
 Muon-spin rotation : a brief introduction
Muons live only for 2.2 us (on average!) - in an experiment, we detect their decay products and these tell us essentially which way each muon-spin was pointing at the moment of death.
SR experiments are performed at the ISIS Pulsed Muon Facility at the Rutherford Appleton Laboratory (close to Oxford) and also at the Paul Scherrer Institute, near Zürich in Switzerland.
Muon spin relaxation techniques have been developed to probe the highly anisotropic motion of the polaronic charge carriers in these polymers.
users.ox.ac.uk /~sjb/musr/musr.html   (482 words)

  
 CERN Courier - Muon ring could act as a neu - IOP Publishing - article
Muons, which are heavy relatives of the electron, come in postively and negatively charged versions with properties that are broadly similar to those of electrons.
As a result of their being more than 200 times as heavy as electrons, muons that are bent by a magnetic guide field lose much less energy than electrons and could be housed in far smaller rings.
However, with muon storage rings, the electrons from muon decay could easily be screened off, providing a pure neutrino beam very close to the intense source.
www.cerncourier.com /main/article/39/6/13   (856 words)

  
 The g-2 Muon Experiment
Muons are subatomic particles known as leptons ('light particles').
The muon is a better probe of new physics at high energy than the electron because of its larger mass.
To create muons, which do not naturally exist, a team of approximately 70 researchers from 11 institutions in the United States, Russia, Japan, and Germany use an accelerator known as the Alternating Gradient Synchrotron to smash protons into a slab of nickel.
www.jupiterscientific.org /sciinfo/muon.html   (1083 words)

  
 Muon
In the Standard Model of particle physics, a muon (from Greek letter mu (μ;) used to represent it) is a semistable fundamental particle with negative electric charge and a spin of 1/2.
The muons created when the pion decays are also short-lived: their decay time is 2.2 microseconds.
However, muons in the atmosphere are moving at very high velocities, so that the time dilation effect of special relativity make them easily detectable at the earth's surface.
www2.hawaii.edu /~spiek/Muon.html   (2079 words)

  
 ScienceDaily: Los Alamos Muon Detector Could Thwart Nuclear Smugglers
Muon radiography uses the natural scattering of muons - produced by the decay of cosmic rays showering down on Earth - as a radiographic probe.
Muons strike the Earth from every angle, so the key to a workable detection system is to keep improving the computer algorithms for tomographic reconstruction.
Muon Opportunists: Detecting The Unseen With Natural Probes (March 10, 2005) -- Earth is showered constantly by particles called muons that are created by cosmic rays, and clever scientists are finding ways to use them as probes of dense objects, including a massive pyramid in...
www.sciencedaily.com /releases/2005/03/050322135547.htm   (1784 words)

  
 D-Zero Muon Systems Upgrade   (Site not responding. Last check: 2007-10-14)
A muon, short for MU-meson, is a lepton with ½ spin whose mass is roughly two orders of magnitude larger than that of the electron.
Due to the mesonic properties of the muon it is unstable an therefore decays fairly rapidly.
It is the responsibility of the muon systems to provide accurate coordinate resolution for a muon passing through the detector in order to efficiently reconstruct the initial collision that "created" the muon in the first place.
sist.fnal.gov /archive/1998-topics/Rodriguez/Html/Paper.htm   (1889 words)

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