Describing weak leptonic processes on the basis of currents with complex coupling constants

Cross sections of elastic (anti)neutrino-electron scattering and neutrino annihilation of an electron-positron pair are obtained and analyzed based on the interaction between diagonal neutral currents and complex or purely imaginary coupling constants.     

Nonperturbative field-theoretical model of leptonic weak interactions

Acta physica Academiae Scientiarum Hungaricae - In this work the problem of the four-leptonic weak processes is studied in the theory with an intermediate vectorW-meson. Neglecting 1.m lept., 2....     

Leading logarithmic corrections to the weak leptonic and semi-leptonic low-energy hamiltonian

If one defines the parameters of the Weinberg-Salam theory at a momentum scale M = O(M_W, M_Z), the weak effective hamiltonian at a momentum scale μ ? M has logarithmically enhanced corrections, of order αln(M²/μ²). We present a computation of these corrections, for that part of the hamiltonian which leads to detectable weak-electromagnetic interference effects. The largest correction can be absorbed into a running sin²θ(μ). Other, smaller, corrections are estimated, taking into account the effect of strong interactions.An estimate of the non-logarithmically enhanced corrections is also given, by evaluating them in the limit sin²θ → 0. From the SLAC e - d asymmetry it was found sin²θ = 0.224 ± 0.020 at μ² ? 2 GeV². In correspondence, we find sin²θ(M) = 0.217 ± 0.020. This value, however, is subject to uncertainties deriving from the effect of the strange and of the antiquark parton sea.     

Non-Hermitian weak hadronic current and the Σ→λ leptonic decay

It is shown that an antihermitian contribution to the isotriplet of weak hadronic strangeness-conserving currents leads to a charge asymmetry. The existence of such currents with “wrong” G-parity is neither established nor refuted by existing experimental data. A deviation of Γ(Σ^?→Λe^?v)/Γ(Σ⁺→Λe⁺v) from the phase space ratio by more than ≈2 percent strongly suggests the presence of an antihermitian weak hadronic current, irrespective of time reversal invariance or CVC being valid or not.     

Unique solution for the weak neutral current coupling constants in purely leptonic interactions

By combining results from the MARK-J at PETRA on Bhabha scattering, μ⁺μ^- and τ⁺τ^- production with recent world data from neutrino-electron scattering experiments, we determine unique values for the leptonic weak neutral current coupling constants g_V and g_A in the framework of electroweak models containing a single Z⁰. In contrast to previous analyses, we only use data from purely leptonic interactions, and therefore avoid the inherent uncertainties resulting from the use of hadronic targets. From the MARK-J data alone in the context of the standard SU(2) ? U (1) model of Glashow, Weinberg and Salam, we find sin²θ_W=0.24±0.11.     

Some weak processes in electron-proton collisions

Polarization effects are investigated for processes of single production of strange particles in electron-proton collisions e^±+p ⁺+e^±. Special attention is paid to effects associated with possible application for investigation of similar processes of polarized electron beams and polarized nucleon targets. We point out the important role of the study of polarization effects for determination of the matrix element of processes of the type e^±+p ⁺+e^±.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 78–82, September, 1990.     

Generalised leptonic colour

It is conceivable that there is an SU?_(N)$\mathit{SU}{(N)}_{?}$ ‘colour’ gauge group for leptons, analogous to the gauged SUq₍₃₎$\mathit{SU}{(3)}_q$ colour group of the quarks. The standard model emerges as the low energy effective theory when the leptonic colour is spontaneously broken. The simplest such generalised leptonic colour models are constructed. We show that the see-saw mechanism for small neutrino masses, along with the theoretical constraint of electric charge quantisation, suggests that the models with N=3$N=3$, 5, 7 are the theoretically most promising cases. A striking feature of generalised leptonic colour is the physics associated with the extra leptonic degrees of freedom—the liptons. These particles can potentially be discovered at future colliders, such as the LHC, making the idea testable in the near future.     

Relaxation polarizations: Strong and weak processes

It has been shown that the through conductivity can differently affect the frequency dependences of the dielectric loss tangent of dielectrics with relaxation polarization. According to this difference, the relaxations in dielectrics are divided into two types: strong and weak. In the case of strong relaxations, the frequency dependences of the imaginary part of the complex conductivity exhibit extrema. Strong and weak relaxations have been investigated in Debye and in non-Debye dielectrics in order to determine the boundary between these processes and explain the existence of relaxations of two types. It has been established that the relaxations in dielectrics can be separated because of the different ratios of the contributions to the polarization of dielectrics from the fast and relaxation polarizations. The corresponding data in the literature are reviewed and the data on the development of strong relaxations in heterogeneous dielectrics are reported.     

Variational processes from the weak forward equation

In this paper the author constructs Markov diffusion processes from a given system of Borel probability measures on ad-dimensional Euclidean space. He constructs a, so-called, variational process which does not always coincide with a Nelson process. He also discusses Schrödinger's problem in quantum mechanics.     

Predictions for the weak leptonic baryon form factors from the hybrid groupSU 3⊗SU 3⊗U 1

Relations between the form factors of the weak leptonic baryon interaction are obtained from invariance under the groupSU ₃?SU ₃?U ₁. The weak interaction operatorV _μ ?A _μ is assumed to behave like the corresponding components of representations35 ofSU ₆ with different parities. One gets the result that the well-known predictions of the staticSU ₆ theory, viz., pureF-coupling for the vector- and 3D+2F-coupling for the axial-vector part, are only valid in the limit of vanishing momentum transfer. In the same limit the resultC _A /C _V =?\(\tfrac{5}{3}\) is obtained if one further assumes thatV ₀ and\(\vec A\) belong to thesame representation35 ofSU ₆.     

Spin-dependent nuclear weak processes and nucleosynthesis in stars

Spin dependent nuclear weak processes and nucleosynthesis in stars are investigated based on recent advances in shell model studies of stable and unstable exotic nuclei. Three topics on (1) neutrino-nucleus reactions in supernova explosions and nucleosynthesis of light elements as well as Mn, (2) electron capture reaction rates on Ni and Co isotopes at high densities and temperatures in the core-collapse process, and (3) new β-decay half-lives of N=126 isotones obtained by including both the Gamow-Teller and the first-forbidden transitions, and the effects on the element abundance in the r-process at the third peak region (A∼195), are studied with the use of new shell model Hamiltonians.     

Strong and weak polarization relaxation processes in solid dielectrics

It is established that an increase in the reach-through electrical conductivity of a dielectric can affect the frequency characteristics of the quantity tanδ in different ways when relaxation polarization processes occur: the extrema of the frequency characteristics can be either suppressed or intensified. In the former case, relaxation processes are referred to as weak; in the latter case, they are referred to as strong. Strong processes lead to the emergence of extrema in the frequency dependence of the imaginary part of complex conductivity. The causes underlying the two polarization relaxation processes are identified.     

Dielectrics with strong and weak processes of polarization relaxation

The relationships between electrical parameters of layers needed both for the transition from strong to weak relaxations and for when there are no extrema in the relation between frequency and the dielectric loss tangent and imaginary parts of dielectric permeability are determined using a model for a double-layered dielectric with the serial inclusion of strata. The literature data was analyzed, allowing us to discover heterogeneous materials with developing strong and weak relaxation polarization. Materials for which the mean time of relaxation for dielectric permeability and conductivity differ were found.