Some technique of reduction of the sdiff(\({\mit \Sigma }^2\)) SDYM equations to the second heavenly equation is proposed. Then it is shown that the same technique leads from the Moyal SDYM equations to the Moyal deformation of the second heavenly equation. The iterative solution of this latter equation is discussed.
The Stückelberg formalism can be regarded as a field-enlarging transformation that introduces an additional gauge symmetry to the considered model. We define and calculate the appropriate BRST charge. The physical state condition, demanding that a physical state is to be annihilated by the BRST charge, is shown to be equivalent to the Stückelberg physical state condition. Several applications of the approach to the formalism are presented. The comparison with the BFV procedure is given.
Starting from Martin, Roberts and Stirling fit for unpolarized deep inelastic structure functions and using experimental data on spin asymmetries we get a fit which provides polarized quark distributions. We analyze the behaviour of such functions near \(x\) equal to 1. The first moments of these distributions are also discussed. Our fit prefers combination of proton and neutron data versus proton-deuteron one.
The vector condensate model is a version of the standard model where the symmetry is broken dynamically by introducing a doublet of vector fields leading to massive spin-one particles (\(B^{\pm }, B^0, \overline {B^0}\)) and preserving the main features of the standard model. The \(B\)-particles are heavy (\(m_B \gtrsim 42.7\) GeV) and the model has a low momentum scale (\(\lesssim 2.6\) TeV). In the present note we point out that \(B\)-particles are copiously produced in \(e^+e^- \to B \bar B, B \bar B Z\) at LEP 200 and high energy \(e^+e^-\) colliders almost in the whole possible mass range.
Interferometry methods have become a well established technique in heavy ion collisions experiments. We present the method for obtaining a more comprehensive information about the spatial structure of source emitting identical particles. It is shown that this information can be extracted by a one dimensional Fourier analysis of the filtered correlation function. Further possible enhancement of the method is sketched. Some technical aspects of the proposed technique are discussed.
The EPOS experiments at the UNILAC accelerator of GSI are reviewed as an example of the development of positron spectroscopy in heavy-ion collisions. The phenomenon of anomalous lines observed in inclusive positron spectra and in electron-positron sum energy spectra as well as the derivation of background of nuclear and atomic positrons is discussed. The article closes with an outlook on a new generation of the experiments currently started with considerably upgraded instruments.
