
	Where results make sense

Topic: Lepton number

Related Topics

Lepton number

leptonic charge

natural number

prime number

atomic number

number theory

cardinal number

ordinal number

rational number

List of elements by number

Mach number

irrational number

In the News (Wed 10 Feb 10)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	Leptons
		Leptons and quarks are the basic building blocks of matter, i.e., they are seen as the "elementary particles".
		There are six leptons in the present structure, the electron, muon, and tau particles and their associated neutrinos.
		Important principles for all particle interactions are the conservation of lepton number and the the conservation of baryon number.
	hyperphysics.phy-astr.gsu.edu /hbase/particles/lepton.html (635 words)

	Lepton number - Wikipedia, the free encyclopedia
		In high energy physics, the lepton number is the number of leptons minus the number of antileptons.
		Lepton number (sometimes also called lepton charge) is an additive quantum number, which means that its sum is preserved in interactions (compared to multiplicative quantum numbers as parity, where the product is preserved instead).
		The lepton number before the reaction is 0 (the neutron, n, is a baryon and therefore there are no leptons before), while the lepton number after the reaction is 0 for the proton +1 for the electron (a lepton) −1 for the antineutrino (an antilepton).
	en.wikipedia.org /wiki/Lepton_number (402 words)

	The Weak Force: Identity or Number Charge
		All elementary particles (the leptons) carry number (identity) charge, which occurs in two forms: 1) a "hidden" form carried by the massive leptons (the electron and its kin); 2) an "explicit" form carried by the (nearly) massless leptons, the neutrinos.
		Number charge is strictly conserved and is observed as follows: every elementary particle - which means every lepton - carries a positive number charge, corresponding to its species, type, or "flavor", and every kind of elementary antiparticle carries an exactly equivalent but negative number charge.
		However, this charge is more specific than simple number, as it is furthermore true that the identity of the leptons involved does not change from one side of the reaction to the other, being carried either as a neutrino, as the massive lepton itself, or in neutral combinations.
	www.people.cornell.edu /pages/jag8/identity.html (2709 words)

	Particle Interactions and Conservation Laws
		Strong overall conservation laws are the conservation of baryon number and the conservation of lepton number.
		This implies that the mesons, with one quark and one antiquark, have a baryon number B=0.
		This rule is a little more complicated than the conservation of baryon number because there is a separate requirement for each of the three sets of leptons, the electron, muon and tau and their associated neutrinos.
	hyperphysics.phy-astr.gsu.edu /hbase/particles/parint.html (1185 words)

	The Naked Scientists Science Discussion Forum - Neutrino Oscillations (Site not responding. Last check: 2007-10-11)
		The lepton numbers before the decay are: muon number 1, electron number 0 and tauon number 0.
		After the decay, the lepton numbers are still the same: muon number 1, electron number 0, tauon number 0.
		In the standard model, total lepton number, as well as each of the electron, muon, and tau lepton numbers are all conserved.
	www.thenakedscientists.com /forum/topic.asp?TOPIC_ID=2179 (494 words)

	Quarks and Leptons
		The standard model of quarks and leptons is a united set of quantum mechanical theories encompassing electromagnetism, the weak force, which is responsible for beta decay, and the strong force, which holds atomic nuclei together.
		The lepton number is the number of leptons minus the number of antileptons, with a similar definition for baryon number.
		Antiparticles are represented by the symbol of the particle with an overbar.
	www.physics.nmt.edu /~raymond/classes/ph13xbook/node209.html (422 words)

	Protons and neutrons
		Decay of the proton would violate the conservation of baryon number, and in doing so would be the only known process in nature which does so.
		The nature of quark confinement suggests that the quarks are surrounded by a cloud of gluons, and within the tiny volume of the proton other quark-antiquark pairs can be produced and then annihilated without changing the net external appearance of the proton.
		The proton in the product satisfies the conservation of baryon number, but the emergence of the electron unaccompanied would violate conservation of lepton number.
	hyperphysics.phy-astr.gsu.edu /hbase/particles/proton.html (1196 words)

	9812360
		There are no indications in favour of violation of the law of conservation of lepton numbers in weak processes and very strong bounds on the probabilities of the lepton number violating processes have been obtained from the experimental data.
		The presence of this phase causes the violation of CP invariance in the lepton sector.
		In this case the number of massive Majorana neutrinos is equal to the number of lepton flavours (three).
	www.nu.to.infn.it /pap/9812360/9812360.html (3305 words)

	Nuclear decays
		The number of baryons must be the same before and after the reaction.
		Anti-electrons and anti-neutrinos are equivalent partices with negative lepton number.
		The electron is necessary to conserve electric charge and the anti-neutrino (the 'anti" being noted by the overbar) ensures the conservation of lepton number.
	www.pa.msu.edu /courses/1997spring/PHY232/lectures/nuclear/decays.html (468 words)

	Baryon Number Generation in the Early Universe (1980)
		Theories in which quarks and leptons are treated in a unified manner often lead naturally to the speculation that there should exist interactions which violate baryon and lepton number.
		lepton numbers were absolutely conserved by all possible interactions occurring in the early universe, then the total baryon and lepton numbers of the present universe must simply reflect their apparently arbitrarily imposed initial values.
		A plausible guess would be that the initial total baryon and lepton numbers were exactly zero (as the total electric charge appears to be).
	www.stephenwolfram.com /publications/articles/cosmology/80-baryon/2/text.html (944 words)

	0102320
		In the case of neutrino mixing, the lepton number (only one) is connected with the nature of massive neutrinos.
		The observation of neutrino oscillations clearly demonstrates that family lepton numbers are not conserved.
		This mechanism is based on the assumption that the law of conservation of lepton number is violated at a scale that is much larger then the scale of violation of the electroweak symmetry.
	www.nu.to.infn.it /pap/0102320/0102320.html (3726 words)

	Physics Help and Math Help - Physics Forums - View Single Post - A third question
		The lepton number is the number of leptons you have.
		[ The number of the anti-particle is the negative of the
		The lepton number after the reaction is +1 + (-1) = 0
	www.physicsforums.com /showpost.php?p=397679&postcount=10 (243 words)

	Cyberphysics - Leptons (Site not responding. Last check: 2007-10-11)
		Leptons do NOT experience the strong nuclear force, rather any nuclear interactions they are involved in are via the weak nuclear force.
		Leptons have zero baryon number and zero strangeness.
		Muonic atoms are much smaller than typical atoms because, in order to conserve angular momentum, the more massive muon must be closer to the atomic nucleus than its less massive electron counterpart.
	www.cyberphysics.pwp.blueyonder.co.uk /topics/physics/particle/lepton.htm (313 words)

	Beta Decay
		Similarly, conservation of lepton number requires that if a neutron (lepton number = 0) decays into a proton (lepton number = 0) and an electron (lepton number = 1), a particle with a lepton number of -1 (in this case an antineutrino) must also be produced.
		The leptons emitted in beta decay did not exist in the nucleus before the decay–they are created at the instant of the decay.
		In beta decay the change in binding energy appears as the mass energy and kinetic energy of the beta particle, the energy of the neutrino, and the kinetic energy of the recoiling daughter nucleus.
	www.lbl.gov /abc/wallchart/chapters/03/2.html (445 words)

	RPGeek@Everything2.com
		Top 5 Writeups with the Most Number of Votes
		Top 5 Writeups with the Least Number of Votes
		lepton number, Pan, constellation, catting weird things to /dev/audio
	www.everything2.com /?node_id=1033930 (706 words)

	[No title]
		A neutron has a baryon number of +1, a lepton number of 0 (because its not a lepton), and a charge number of 0 (its neutral).
		So now we have a lepton number of +1 on the decay side when the initial value was zero.
		These are absurd numbers of course and we have no real clue what kind of physics is occurring here nor even what the meaning of "space" is under such extreme conditions.
	zebu.uoregon.edu /1998/ph301/hb/c3w.html (7082 words)

	[No title]
		Their antiparticles have a lepton number -1 whereas meason and baryons are assigned a lepton number of zero.
		By imposing the constraint that lepton number must be conserved in particle reactions, particle physicists can explain why neutrinos and sometimes antineutrinos (or sometimes both in the case of muno decay) must be observed.
		The totoal baryon number is +2 on both sides therefore B is conserved and the reaction is possible.
	www.ph.surrey.ac.uk /partphys/chapter6/laws.html (1194 words)

	Photons, Neutrinos, And Their Anti-Particles
		If the only distinction between the neutrino (L=+1) and the anti-neutrino (L=-1) is their helicity, and if this is not Lorentz-invariant, then it seems to follow that lepton number is not conserved, and the absolute distinction between neutrino and anti-neutrino disappears.
		It would be on the same footing as the electron or the muon, which also are Dirac fermions, which have a mass and lepton number, two possible helicities and an anti- particle, which also has two possible helicities, but opposite charge and lepton number.
		Such a neutrino would indeed violate lepton number conservation and the search for lepton number violating processes is actually a matter of current experiments.
	www.mathpages.com /home/kmath246.htm (1226 words)

	Neutrino Mass and Mixing (Site not responding. Last check: 2007-10-11)
		In the standard model of elementary particles distinct lepton numbers exist (L_e, L_mu and L_tau).
		Indeed, in the standard model, the lepton masses originate from a Yukawa-type coupling of the lepton fields to the vacuum expectation value of the Higgs field.
		Also, oscillations could occur between the neutrino and the anti-neutrino and thus violate the conservation of the total lepton number (Majorana neutrinos).
	www.phy.duke.edu /~rps/coll99/ludwig.html (191 words)

	Glossary: SLAC Virtual Visitor Center
		number are further types of "charges" that are reversed for particle and antiparticle.
		The polarization of the beam is the fraction of the particles with the desired alignment.
		A number that labels a state, it denotes the number of quanta of a particular type that the state contains.
	www2.slac.stanford.edu /vvc/glossary.html (5563 words)

	Theory: Conservation Laws
		and not quarks, this is usually stated as baryon number conservation, where baryon number is the same as quark number divided by 3.)
		Within the Standard Model, the three lepton number laws (7, 8,9) are separate conservation laws if neutrinos have zero mass.
		If these results are confirmed, the lepton number laws may be downgraded to the status of approximate conservation laws.
	www2.slac.stanford.edu /vvc/theory/conserv.html (370 words)

	Re: The life of elementary particles
		Protons have a baryon number of 1 and a lepton number of 0, while positrons have a baryon number of 0 and a lepton number of -1 (negative because a positron is an anti-electron and an electron has a lepton number of +1).
		Pions have baryon number 0 and lepton number 0.
		In fact, grand unified theories (GUTs) predict that baryon number and lepton number are violated at some high energy E_gut, and hence also that protons decay.
	www.madsci.org /posts/archives/may2001/989934620.Ph.r.html (685 words)

	[No title]
		If this process were to be found, it would be evidence of the violation of a supposedly conserved quantity known as lepton number.
		Thus, in the normal beta decay process, the initial and final lepton numbers are both zero.
		This is an example of lepton number conservation; no experiment to date has detected a violation of this conservation law.
	www.dushkin.com /text-data/weekly/cp02-25-02.mhtml (777 words)

	Searches for Nucleon Decay at Super-Kamiokande
		But consider the proton, which is a collection of three quarks not a single particle, one might expect it to decay to, say, a charged lepton and a neutral meson or a neutral lepton and a charged meson by having one of the quarks turn in to a lepton.
		However, in changing a quark to a lepton a quantity called Baryon number is changed overall (as is Lepton number).
		By far the most numerous is when atmospheric neutrinos interact via charged current with the nucleons in the water and some number pions are created along with the outgoing lepton.
	ale.physics.sunysb.edu /superk/physics/nucleon-decay (916 words)

	Re: Which particles are their own anti-particles?
		If neutrinos were their own antiparticles, then lepton number would not be conserved.
		Some people believe that the numbers of leptons and antileptons were equal in the very early universe.
		In that case, processes which violate lepton number conservation would be needed to explain the current state of the universe, where the number of leptons appears to be greater than the number of antileptons.
	www.madsci.org /posts/archives/aug2000/965674158.Ph.r.html (226 words)

	neutrino decay
		Baryon number and lepton number are accidental symmetries of perturbation series in the standard model.
		Now if lepton number is not conserved, by some extension of the sm, then yes neutrinos should be able to decay.
		Except that they are extremely light, and no lighter leptons have ever been observed, hence by phase space arguments the electron neutrino should remain stable under decays.
	www.physicsforums.com /showthread.php?t=62892&goto=nextoldest (1048 words)

	Extracting Half-lives from Characteristic Gamma Spectra
		Similarly, conservation of lepton number requires that if a neutron (lepton number = 0) decays into a proton (lepton number = 0) and an electron (lepton number = 1), a particle with a lepton number of –1 (in this case an antineutrino) must also be produced.
		The leptons emitted in beta decay did not exist in the nucleus before the decay – they are created during the process of decay.
		The number of protons (and neutrons) in the nucleus does not change in this process, so the parent and daughter isotopes are the same.
	ie.lbl.gov /radioactivedecay (2296 words)

	A Closer Look At Hadrons (1)
		Hadrons are elementary particles that are subject to both the strong and the weak force.They are composed of smaller entities termed 'Quarks'.Click here to see a brief overview of quarks.
		Even with baryon number B,lepton number L and electric charge Q, certain elementary particle events could not be esplained fully.
		The strangeness quantum number S is conserved in all strong interactions but may change in a weak interaction.
	www.egglescliffe.org.uk /physics/particles/hadron1/hadron1.html (664 words)

	Theory of Neutrino Mass
		The simplest implementation is the Gelmini-Roncadelli (GR) model [6], in which lepton number is spontaneously broken by
		Variant models involving explicit lepton number violation or in which the Majoron (the Goldstone boson associated with lepton number violation) is mainly a weak singlet (invisible Majoron models) are still possible.
		A very different class of models are those in which the neutrino masses are zero at the tree level (typically because no Weyl singlets or elementary Higgs triplets are introduced), but only generated by loops [10], i.e., radiative generation.
	dept.physics.upenn.edu /~pgl/neutrino/jhu/node2.html (775 words)

	conservation laws
		Again, leptons have lepton number of +1, antileptons have -1, and non-leptons have 0.
		Charge is conserved, but lepton number is not.
		There are no leptons on the left, but there is one on the right.
	quarknet.fnal.gov /toolkits/ati/conservation.html (558 words)

Try your search on: Qwika (all wikis)