Muon number conservation

The muon and the electron may be considered to belong to two different generations of leptons, which thus far appear to remain separate because of the independent conservation laws of muon number and of electron number. Any connection between the muon and the electron, such as a process which would violate muon number conservation, would be an important clue to the relationship... 

Violates additive conservation law for muon number, EL constant. 

Present experimental evidence and the standard electroweak theory are consistent with the absolute conservation of three separate lepton numbers electron number Le, muon number and tau number T,-. Searches for violations are of the following types ... 

Second Quantized Description of a System of Noninteracting Spin Particles.—All the spin particles discovered thus far in nature have the property that particles and antiparticles are distinct from one another. In fact there operates in nature conservation laws (besides charge conservation) which prevent such a particle from turning into its antiparticle. These laws operate independently for light particles (leptons) and heavy particles (baryons). For the light fermions, i.e., the leptons neutrinos, muons, and electrons, the conservation law is that of leptons, requiring that the number of leptons minus the number of antileptons is conserved in any process. For the baryons (nucleons, A, E, and S hyperons) the conservation law is the... 

One of our main interests is to describe quark matter at the interior of a compact star since this is one of the possibilities to find color superconducting matter in nature. It is therefore important to consider electrically and color neutral2 matter in /3-equilibrium. In addition to the quarks we also allow for the presence of leptons, especially electrons muons. As we consider stars older than a few minutes, when neutrinos can freely leave the system, lepton number is not conserved. The conditions for charge neutrality read... 

One is based on a study of the possibility of the conversion of muonium f/i+e -system) to antimuonium (p e+-svstem) [12]. This is possible in the case of non-conservation of electronic charge (i.e. the number of electrons and electronic neutrinos minus the number of positrons and antineutrinos) and muonic charge (i.e. the number of muons and muonic neutrinos minus the number of their antiparticles). Both must be conserved separately with the Standard Model. 

Taking the fact that at 16 hPa 4% of all muons reach the 2S state and assuming a conservative number for the slowing down probability of pp(2S) initially formed at energies above 0.31 eV, we can give a preliminary number of 1.5% for the fraction of metastable np(2S) per muon stopped in hydrogen. 

A plethora of experiments involving the neutrino revealed some remarkable properties for this new particle. The neutrino was found to have an intimate connection with the electron and muon, and indeed never appeared without the simultaneous appearance of one or other of these particles. A conservation law was postulated to explain this observation. Numbers were assigned to the electron, muon, and neutrino, so that during interactions these numbers were conserved i.e. their algebraic sums before and after these interactions were equal. 

Leptons, which include the electron, the neutrino, and the muon, have lepton number +1, and antileptons have lepton number —1 all other particles have lepton number 0. There is rigorous conservation of the lepton number in all reactions. 

The three-body decay of muons includes a charged electron and a neutrino and antineutrino, each of the type or flavor to conserve a separate lepton number, i.e one muon type and one electron type, while the meson (pion or kaon) decay produces almost exclusively muon type neutrinos or antineutrinos (see Table I). As a consequence, atmospheric neutrinos interacting in a detector such as K-II or SuperK would be expected to produce, on average, twice as many muons as electrons. The double ratio / meas (no. of muons/no. of electrons) divided by / caic (no. of muons/ no. of electrons) was explored in K-II and subsequently in Super K, and the results are shown in Table VI, where it is seen that apart from one experiment (Frejus less than three standard deviations from the average of the other experiments), the double ratio / meas// caic is significantly different from the expected value of unity. 

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