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Topic: W particles

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	Exchange Particles
		Gluons are the exchange particles for the color force between quarks, analogous to the exchange of photons in the electromagnetic force between two charged particles.
		The W and Z particles are the massive exchange particles which are involved in the nuclear weak interaction, the weak force between electrons and neutrinos.
		The charged W bosons participate in the transformation of quarks in which the flavor of the quark is changed.
	hyperphysics.phy-astr.gsu.edu /hbase/particles/expar.html (1159 words)

	W and Z particles - HighBeam Encyclopedia (Site not responding. Last check: 2007-10-12)
		W and Z particles elementary particles that mediate, or carry, the fundamental force associated with weak interactions.
		The discovery of the W and Z particles at CERN near Geneva, Switzerland, in the early 1980s was an important confirmation of electroweak theory, which unifies the electromagnetic and weak forces.
		The W and Z particles are quite massive for elementary particles; they are roughly 100 times as massive as the proton.
	www.encyclopedia.com /doc/1E1-WNZparti.html (377 words)

	W and Z bosons Summary
		The second type consists of mediating particles that transmit the four fundamental forces, namely the graviton (for the gravitational force), the gluon (for the strong force), the photon (for the electromagnetic force) and the W and Z bosons (for the weak force).
		The existence of W and Z bosons was predicted as a consequence of the electroweak theory developed by Steven Weinberg, Abdus Salam, and Sheldon Glashow in the early 1970s.
		In physics, the W and Z bosons are the elementary particles that mediate the weak nuclear force.
	www.bookrags.com /W_and_Z_bosons (1776 words)

	Event types (Site not responding. Last check: 2007-10-12)
		During the second phase of LEP, which started in 1996, the energy of the colliding particles are set such that a pair of W particles can be produced.
		The mass of W is around 80 GeV, so the energy of each colliding particle has to be at least 80 GeV to be able to produce two W particles.
		The Z and W particles are produced almost at rest as almost all the collision energy goes into producing the particles.
	www.lip.pt /~dellip/PT_HandsOnCern/hub/evtyp.html (479 words)

	A letter on quarks and weak interactions
		The photon, quantum of the EM force, is a superposition of W3 and B states, and the Z is another superposition of the two; the W+ and W- are superpositions of the W1 and W2.
		The W is also far off shell in the low-energy situation of ordinary beta decay, which, in the GWS model, is why weak interactions happen at such a slow rate compared to other kinds.
		The W was actually first proposed long before Glashow, Weinberg, and Salam put the electroweak theory together, but it took a set of powerful new concepts (the combination of gauge theory and spontaneous symmetry breaking) to create a consistent and realistic theory with a W in it.
	world.std.com /~mmcirvin/weak.html (1009 words)

	Cosmology & Particle Physics FAQ
		Not unlike the reflection in a mirror, there is exactly one antimatter particle for each known particle and they behave just like their corresponding matter particles, except they have opposite charges and/or spins.
		The carrier particles of the weak force are the W+, W-, and the Z bosons.
		Only the W and Z particles, mediators of the weak nuclear force, are massive, and the W+ and W- particles carry charge.
	www.thebigview.com /spacetime/faq.html (1733 words)

	Highlights from Run 1
		Three of the Higgs particles are absorbed in giving the W and Z their masses, while the last one remains to be discovered; its mass is not predicted, but can be inferred in the framework of the SM from precision measurements of other quantities.
		W bosons are produced at the Tevatron mainly when a quark from a proton and an antiquark from an antiproton collide head-on at the DØ detector.
		A quantity called the transverse mass of the W boson is then calculated by combining the transverse momenta of the electron and neutrino, and the mass of the W is extracted from the shape of this transverse mass distribution.
	www-d0.fnal.gov /~klima/highlights_v18.htm (8621 words)

	Metaworld Page2 CONTINUED
		Particles in a box, lowest energy state achieved by all of them occupying lowest energy level.
		Solid-state analogue of higgs particle is a cooper pair of electrons, thus higgs particle may not be a genuine elementary particle but a composite.
		but not (w/ exchange electric and B fields) +Dirac showed existence of 1 quantum mechanical magnetic monopole would imply all electric charges must be exact multiples of the charge of the electron.
	interzone.com /~cheung/Page.dir/pg.metaworld2a.html (2611 words)

	How to navigate (Site not responding. Last check: 2007-10-12)
		Particle collisions are used to study the smallest building blocks in Nature - the quarks and the leptons.
		Particles like the electron can be identified as a charged particle giving away all its energy in one of the energy detectors and the muon is the charged particle that goes through all the detectors almost without being affected at all.
		At LEP1, the first phase of the accelerator, single Z particles are produced, while at LEP2, the second phase of the accelerator that will run until year 2000, pairs of Z or W particles can be produced.
	www.lip.pt /~dellip/PT_HandsOnCern/hub/howto.html (627 words)

	Particle Analysis - Studies
		An example of a large aggregate of W (with Co) particles from the interior wall is shown.
		In contrast, the W-bearing particles identified in the nearby garden soil were, in general, not associated with Co or Ca.
		This lack of an association with Ca might suggest that the material in the soil is derived from the plant interior (exhausted to the external environment and atmospherically dispersed) rather than originate as fugitive emissions from the debris heap.
	www.upstate.edu /pathenvi/studies/case1.html (819 words)

	New Scientist: Hunting the higgs (Site not responding. Last check: 2007-10-12)
		To pursue the analogy, we might think of the North Pole as being analogous to the basic particles that transmit the weak interactions while the equator is similar to the photon, which is the basic unit or quantum of light.
		Forces between particles are transmitted by other particles, such as photons, the carrier of electromagnetic forces, and W and Z particles, the basic particles that transmit the weak interactions.
		The Higgs particle is the quantum of a new field called the Higgs field, which was zero in the very early Universe, but turned on as the expanding Universe cooled-just as the motion of the Earth emerged when it condensed out of the dust and gas surrounding the early Sun.
	www.umich.edu /~mctp/media/huntinghiggs.html (2299 words)

	Quantum Overview/2
		The Zo, W+ and W- bosons transmit the weak force; their existence was predicted by the unified theory of the weak and the electromagnetic interactions, and their discovery vindicated the theory.
		In the case of electromagnetism this is the phase of the wave and in gravity it is the relativistic transformations of space-time.
		Particles are divided into half-integer spin fermions which obey the Pauli exclusion principle and can only exist in a single wave-function in pairs, thus becoming matter, and integer-spin particles called bosons, which can clump in any number (lasing) and thus form the radiation and force fields.
	www.dhushara.com /book/quantcos/quant1/quantsb.htm (3102 words)

	A Model for the Deposition of Hydrothermal Manganese
		Cowen and Li [1991] suggest that only a small fraction of the fine particles, specifically the metal scavenging capsuled bacteria, are responsible for the bulk of the dMn scavenging.
		This corresponds to the Stokes settling speed of, for example, 1.9 µm diameter particles with specific gravity 2.6 or 3.2 µm particles with a specific gravity of 1.55.
		Particles in this size range have been documented in hydrothermal plumes of the southern JDFR [Walker and Baker, 1988].
	www.pmel.noaa.gov /pubs/outstand/lave1285/values.shtml (2001 words)

	Press Release: The 1984 Nobel Prize in Physics
		One expected on theoretical grounds that the weak interaction is communicated by extremely heavy hypothetical particles, W and Z. In 1976 Carlo Rubbia presented an idea to convert an existent large accelerator into a storage ring for protons and antiprotons.
		The discovery of the W and Z were announced in 1983 by Rubbia and collaborating large teams of scientists, basing the evidence on signals from detectors, specially designed for this task.
		The discovery of the heavy field particles W and Z culminates 50 years of scientific investigations of the nature of the weak interaction.
	nobelprize.org /nobel_prizes/physics/laureates/1984/press.html (1220 words)

	E158 Parity Violation
		P violation occurs when the rate for a particle interaction is different for the mirror image of that interaction.
		particles) scattering interactions was first observed at SLAC in 1978, by Charles Prescott and collaborators studying the scattering of electrons from protons in a liquid deuterium target.
		However, CP was observed to be violated at a small level in the weak interactions of kaons (particles that contain a down-type quark and a strange-type quark) in 1964 by James Cronin and Val Fitch and collaborators, for which they won the Nobel Prize in physics in 1980.
	www-project.slac.stanford.edu /e158/parityviolation.html (733 words)

	Carlo Rubbia Summary
		One consequence of the theory was the prediction that three new force-carrying particles, the W+, W-, and Z0 boson existed.
		The existence of these particles had been predicted in the 1960s, when Sheldon Glashow, Abdus Salam, and Steven Weinberg had independently developed an electroweak theory proposing that two fundamental forces, the electromagnetic and weak forces, are manifestations of a more fundamental natural force, and predicting the existence of W and Z particles.
		Within a month's time, the first W particles had been identified and, less than a year later, the first Z's were also discovered.
	www.bookrags.com /Carlo_Rubbia (2074 words)

	Learning What Is,From What Doesn't : Alan H.Guth
		The W particle decays in the third step into a neutrino and an electron, and in the fourth step, the neutrino combines with the W+ to form a positron.
		In fact, the W+ and W particles were not actually observed until 1983, when a mammoth experiment performed by a team of 135 physicists led to the observation of six W particles.
		The particle was called J on the East Coast and psi on the West Coast, so today it is known by the compromise name J/psi.
	members.fortunecity.com /templarser/whatdoes.html (2094 words)

	Feynman Diagrams and Forces Between Particles
		If the electromagnetic field is defined in terms of the force on a charged particle, then it is tempting to say that the field itself consists of photons which cause a force on a charged particle by being absorbed by it or simply colliding with it - as in the Photo-electric effect.
		The W particles carry the electric charge and when they are emitted or absorbed by a particle they change its identity.
		As the strength of a force is proportional to the probability of emitting a boson, the weakness of the weak force implies that this decay is a rare event and that the neutron is fairly stable.
	www.egglescliffe.org.uk /physics/particles/parts/parts1.html (1055 words)

	CERN Courier - Neutral currents and W and Z - IOP Publishing - article
		The observation of W particles by the UA1 and UA2 experiments was announced at CERN on 20 and 21 January 1983.
		With the discovery of the W and Z particles, electroweak theory became truly established.
		The discovery of the W and Z particles owed much to the development of detector techniques, in particular by Georges Charpak at CERN, who was rewarded with the Nobel prize in 1992.
	www.cerncourier.com /main/article/43/10/21/1 (1316 words)

	ALR homepage
		particles transmit the weak force (radioactivity is an example of a weak force interaction) and do so with different strengths for right-handed and left-handed particles.
		The Higgs particle interacts with all types of matter and force particles, and is responsible for generating their masses.
		If the Standard Model is correct, established measurements of the Z particle mass at CERN and the top quark mass at Fermilab now allow predictions for the Higgs' mass from accurate measurements of the weak mixing angle and from other precision measurements, such as the mass of the W particle.
	www-sldnt.slac.stanford.edu /alr (1189 words)

	Quarks and Leptons
		The leptons are the electrons, muons and tau particles, along with their corresponding neutrinos (and, as always, their antiparticles).
		Below are two charts showing the basic constituents of matter (the particles) and the forces that mediate interactions between these particles.
		The photon mediates electromagnetic interactions; W and Z particles are involved with interactions involving nuclear decay.
	members.tripod.com /w.g.seeley/scitech/quarks1.htm (215 words)

	katherine copic at cdf
		The force that I study is the weak force, and its particles are called the W+, W- and Z bosons.
		In particle physics, we study the weak force by making the W and Z bosons at Fermilab, measuring their properties (like their masses) and studying their production (how often we make them) and their decay (what they decay into).
		With well-identified samples of W's and Z's we can examine their properties, as part of a program to understand one of the basic forces in nature.
	www-personal.umich.edu /~kcopic (530 words)

	Allowed and Forbidden Particle Decays (Site not responding. Last check: 2007-10-12)
		Discrete particles tend to be unstable and to decay into two or more particles of lesser mass unless they are forbidden to do so by some principle or conservation law.
		They involve quark transformations involving the W particles to change quark flavors.
		Besides tracking the quark content of the particles, it is helpful to examine the Feynmann diagrams for W decay to see what the usual decay products are.
	hyperphysics.phy-astr.gsu.edu /hbase/Particles/allfor.html (382 words)

	what's the matter notes session 5
		These W particles play the same role in the weak interaction that the photon plays in QED.
		It is the massiveness of these particles that is responsible for the fact that the weak force is a short range force.
		This particle has not been observed, and there are some theoretical reasons to doubt that it is fundamental -- it might be a bound state of as yet unknown fermions.
	homepage.mac.com /stevepur/physics/matter/matter.5.html (923 words)

	The Particles
		Historically, when patterns emerge in a collection of particles, this is an indication of the substructure of the particles.
		This fact, along with the fact that particles must decay to lighter particles, and a couple of other constraints, is the reason that some particles, such as electrons, protons, and neutrons (inside nuclei) are stable (don't decay, or at least don't decay for a very long time).
		The W's and the Z are quite heavy by particle standards (over 80 times the mass of a proton!) and are unstable.
	webs.morningside.edu /slaven/Physics/micro/micro2.html (1474 words)

	The Small Picture
		So what we refer to as the Z particle is actually part gauge boson, and part Higgs particle, and it's this absorption of the Higgs particle that gives the Z (and the W's) its mass.
		A supersymmetric theory is a theory in which every particle I've mentioned so far has a companion particle with similar properties, but with a different spin (a property I mentioned earlier, but if you forgot, don't worry about it) and a much heavier mass.
		The particles that make up these particles are held together by a "technicolor" force that is similar to the "color," or strong force.
	webs.morningside.edu /slaven/Physics/micro/micro10.html (1390 words)

	Mechanism of lung injury caused by PM10 and ultrafine particles with special reference to COPD -- MacNee and Donaldson ...
		Particles that are <100 nm in diameter are commonly
		MacNee W, Rahman I. Is oxidative stress central to the pathogenesis of chronic obstructive pulmonary disease?.
		Stone V, Shaw J, Brown DM, MacNee W, Faux SP, Donaldson K. The role of oxidative stress in the prolonged inhibitory effect of ultrafine carbon fl on epithelial cell function.
	erj.ersjournals.com /cgi/content/full/21/40_suppl/47S (2744 words)

	Spherotech
		The polystyrene particles are prepared by using emulsion polymerization process.
		Particles supplied by Spherotech have been precleaned using either mixed bed ion exchange or by centrifugation.
		The size of particles is determined by either NICOMP Laser Particle Sizer or visually by Scanning Electron Microscope.
	www.spherotech.com /pol_par.htm (703 words)

	Physics News Graphics: Newly Identified Top-Quark Decay Modes
		Emerging from the fireball of a proton-antiproton collision, a top quark and its antitop twin quickly decay into a total of four particles--a pair of W bosons, a bottom quark (b), and an antibottom quark (b bar).
		(2) A rare decay mode is the "dilepton mode" in which each W particle decays into a lepton (such as an electron or muon) plus a neutrino.
		(3) In the "lepton-plus-jets" mode, one W decays into a lepton (such as an electron or a muon) plus a neutrino while the other W decays into two quarks, which subsequently produce a "jet," or spray of particles.
	www.aip.org /png/html/topdecay.htm (566 words)

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