Leptonic Weak Interactions Research Articles

Comments on the production and decay of charged heavy leptons

Several issues concerning charged heavy leptons (L/sup + -/) are considered for the production and decay sequence e/sup +/ + e/sup -/ ..-->.. L/sup +/ + L/sup -/ ..-->.. decay products. We note that certain angular distributions of decay products contain information on the L/sup +/L/sup -/ production process independent of any details of the decays. For leptonic decays L ..-->.. ..nu../sub L/ + l + anti ..nu../sub l/ (l = e or ..mu..) other aspects of the joint energy and angular distributions provide further information concerning the helicity structure of the weak leptonic interactions. Several other issues concerning semileptonic decays are also discussed. In particular, some special cases are described where parity-violating effects would uniquely signal the presence of second-class currents. (AIP)

On the Non-Leptonic Decays of the Charmed Baryons

Assuming the 15-Hamiltonian, the non-leptonic decays of the charmed baryons including (3/2r baryon are examined. The results are compared with those of 20'' -dominance. Our results are also compared with the recent experimental data. § l. Introduction Since Niu et al.v found in the nuclear jet shower a charged massive particle 2 J~GJ about it were given. Ogawa et al. 2J presented an interpretation of this event on the basis of the revised New Nagoya Model6J for the urbaryons (the constituents of hadrons), and pointed out that this particle may be a new hadron (hereafter called the charmed hadron) which includes the fourth urbaryon Po' in the New Nagoya Model, and also in­ vestigated the weak decay rates of the charmed hadrons. Nakagawa et al.sJ.•J also discussed masses and the interaction scheme of charmed hadrons in the framework of the SU(4) symmetry and showed that, taking the New Nagoya Model, all non­ leptonic weak interactions with [LIS[ =1 and/or [LIN'[ =1, where N' is the Po' number (charm number), belong to a representation 84 when the V-A current­ current interaction is taken. *l They have further pointed out that 84 interaction Hamiltonian, together with LII = 1/2 rule, leads to the vanishing of the amplitudes of the ordinary hyperon decays so that the usual enhancement of octet representa­ tion of SU(3) may be ascribed to the enhancement of 15 spurion through a breaking interaction. The present author and othersn have shown the relations among the amplitudes of the charmed baryon decays CV-+t++o-) for [LIS[ =1, LIN' =0 and LIS=O, [LIN'[ =1 processes taking 15-Hamiltonian similarly to Nakagawa

Quark-lepton analogy and neutrino oscillations

A theory of the weak interactions of leptons which is analogous to that of the weak interaction of the four quarks is considered. Mixing of neutrinos (with finite masses) is introduced and arguments are given in favour of maximum mixing. Physical consequences of the theory are discussed with emphasis on neutrino oscillations.

Gauge theory with calculable neutron-proton-quark mass difference

A gauge theory of weak and electromagnetic interactions is presented, in which the neutron-proton-quark mass difference is finite and calculable. The model is a generalization to include strange particles of an $\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(2)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{U}(1)$ model suggested by Weinberg; neutral strangeness-changing processes are suppressed using the Glashow-Iliopoulos-Maiani mechanism, which introduces a fourth "charmed" quark ${\mathcal{P}}^{\ensuremath{'}}$, in addition to the usual $\mathcal{P}$, $\mathfrak{N}$, $\ensuremath{\lambda}$. Universality of semileptonic and leptonic weak interactions can easily, though not naturally, be achieved, and the model has the interesting prediction that the effective hadronic neutral current is purely vector. By imposing an additional discrete symmetry, a solution is obtained in which weak universality is natural, and the neutron-quark and proton-quark masses vanish in zero order.

Symmetries of Neutral Weak Currents

The U2 × U2 and D symmetries of the leptonic weak interaction are extended, within the framework of the quartet–quark model, so as to include the hadronic weak interaction. The total weak current satisfies a lepton–quark symmetry. Application of these symmetries to the neutral current weak interaction restricts the current to be composed only of vector and axial vector pieces, and also restricts the symmetry properties of its (V−A) part. Experimental implications of these symmetries in various neutrino reactions are investigated. There are some ambiguities as regards the (V+A) part of the neutral current, which may, however, be resolved soon if more experimental data become available.

Finite unitary theory of pure leptonic weak interaction

Based on the V-A interaction, a finite, unitary theory of pure leptonic weak interaction is formulated in the framework of the finite quantum field theory with shadow states. A perturbative series, originated from the conventional expansion is obtained. This new perturbative series converges in the high energy region where the original one does not. The difference between the prediction of this theory and the universal V-A theory is negligible in low energy regions but becomes significant in high energy regions. (auth)

Erratum: Simple relations among leptonic weak interactions

Erratum: Simple relations among leptonic weak interactions

Weak interactions at short distances

The weak interaction increases with lncreasing energy. The form of the interaction is presented. Real processes at high energy include: elastic scattering of leptons, the interaction of the neutrino with nucleons, inelastic scattering of leptons, lower limit for elastic e/sup +/e/sup -/-scattering cross section, the behavior of the total cross sections of the weak interactions of leptons at energies above the unitary limit. Under virtual processes the review covers: lepton interactions, electromagnetic interactions of leptons, weak interactions of leptons such as mu -decay, elastic nu /sub e/ e/sup -/- scattering, elastic nu /sub mu / e/sub e/-scattering and ela stic e/sub e/- scatiering, hadron--lepton interactions, weak neutral currents, ratio of vector constant of BETA - and mu -decay, nonleptonic interactions, and hadron processes with a change in strangeness, parity or isotopic spin. Also attempts to construct a new theory of weak interactions are considered. 114 references. (SJR)

Simple Relations Among Leptonic Weak Interactions

In the weak intermediate-vector-boson theory, it is shown that at least one of the effective coupling constants for the leptonic weak interactions, (1) ( nu /sub 1/V/sub 1/ (ll), (2) (ll) (ll), and (3) ( nu /sub 1/ n/sub 1/ ( nu /sub 1/ nu /sub 1/), is not smaller he Fermi coupling constant) and that all the compling constant for (1) and (2) cannot vanish simultaneously unless the coupling constant for (3) is infinitely large. (auth)

Слабые взаимодействия на малых расстояниях

The weak interaction increases with lncreasing energy. The form of the interaction is presented. Real processes at high energy include: elastic scattering of leptons, the interaction of the neutrino with nucleons, inelastic scattering of leptons, lower limit for elastic e/sup +/e/sup -/-scattering cross section, the behavior of the total cross sections of the weak interactions of leptons at energies above the unitary limit. Under virtual processes the review covers: lepton interactions, electromagnetic interactions of leptons, weak interactions of leptons such as mu -decay, elastic nu /sub e/ e/sup -/- scattering, elastic nu /sub mu / e/sub e/-scattering and ela stic e/sub e/- scatiering, hadron--lepton interactions, weak neutral currents, ratio of vector constant of BETA - and mu -decay, nonleptonic interactions, and hadron processes with a change in strangeness, parity or isotopic spin. Also attempts to construct a new theory of weak interactions are considered. 114 references. (SJR)

On the Diagonal Part $({\bar{\mu}} {\nu}_{\mu})(\bar{\nu_{\mu}}{\mu})$ in the Theory of Leptonic Weak Interactions

On the Diagonal Part $({\bar{\mu}} {\nu}_{\mu})(\bar{\nu_{\mu}}{\mu})$ in the Theory of Leptonic Weak Interactions

A theory of universal weak interaction of leptons

A theory of universal weak interaction of leptons

Leptonic and semi-leptonic weak interactions

New results on leptonic and semi-leptonic weak processes are reviewed. Recent references on this subject are accumulated.

Symmetry of Leptonic Weak Interactions and Lepton Mass Spectrum

The invariance principle that excludes the neutral leptonic currents and uniquely determines the leptonic weak interactions is discussed. Based on symmetry considerations and the existence of two different neutrinos, we suggest that the neutrino masses are not strictly zero and there are new heavy charged leptons and their neutrinos. A possible lepton mass spectrum is obtained.

Weak Interactions at High Energies

We discuss the weak interactions from an $S$-matrix point of view in order to make some qualitative statements about high-energy behavior. In order to separate the weak interactions from others as much as possible, attention is focused on the weak interactions of leptons neglecting electromagnetism. We examine the consequences of imposing the constraints of unitarity and analyticity on weak amplitudes whose low-energy behavior is assumed to be correctly given by the usual Fermi theory (including the possibility of neutral currents). We first study corrections to the low-energy limit by using the Mandelstam iteration to express all lepton-lepton two-body scattering amplitudes to third order in the Fermi constant in terms of a small number of subtraction constants. We then speculate beyond perturbation theory. We discuss some consequences of forward dispersion relations and propose a mechanism for providing the necessary damping of weak amplitudes at high energies. The mechanism is the existence of the intermediate vector boson coupled weakly to leptons but interacting strongly with itself. We examine some consequences of this hypothesis.

Physical Processes in a Convergent Theory of the Weak and Electromagnetic Interactions

A previously proposed theory of leptonic weak and electromagnetic interactions is found to be free of the divergence difficulties present in conventional models. The experimental implications of this theory and its extension to hadrons are briefly discussed.

Prediction for neutrino-electron cross-sections in Weinberg's model of weak interactions

Weinberg's theory of purely leptonic weak interactions can be tested in neutrino-electron scattering experiments. Cross-sections must be measured as a function of the energy of the recoil electron. If Weinberg's theory is correct, then the masses of the intermediate vector bosons can be derived from the measured effective coupling constants.

Vertex function in the theory of the weak interaction of leptons

Vertex function in the theory of the weak interaction of leptons

Neutrino-adron processes in a system of weak interactions, including a third neutrino

A scheme is discussed for describing weak interactions of leptons and adrons, including the “strange”" s-neutrino. It is suggested that the s-neutrino, which is different from the electron and muon neutrino, originates by lepton decays of hyperons and kaons. The possibilities are discussed for the experimental verification of the hypothesis concerning the existence of the third neutrino.

Kinematical Distributions of Neutrino-Produced Lepton Triplets

Differential distributions in lepton triplets ${\ensuremath{\nu}}_{\ensuremath{\mu}}{\ensuremath{\mu}}^{\ensuremath{-}}{\ensuremath{\mu}}^{+}$, ${\ensuremath{\nu}}_{e}{\ensuremath{\mu}}^{\ensuremath{-}}{e}^{+}$, ${\ensuremath{\nu}}_{e}{e}^{\ensuremath{-}}{e}^{+}$ produced from neutrinos through the point four-fermion interaction and single-photon exchange with a nuclear target have been calculated using a Monte Carlo method. These are fundamental processes which can be calculated to arbitrary accuracy, and which test aspects of the leptonic weak interactions, in particular diagonal processes, which are not accessible to other tests. The calculations cover energies from 1.5 to 40 GeV, and targets of mass 1, 12, 56, and 208. Salient features of the results are that typically the negative lepton is energetic, the positive one much less energetic, and transverse momenta of the charged leptons are quite large (100-200 $\frac{\mathrm{GeV}}{c}$ at 15 GeV).