It is shown that a previous inclusion of electromagnetic material field in the generalised field theory using gauge structures is inconsistent with the theory itself. The derivation of the field equations is reviewed and the full equations of the electromagnetic field are found. The resulting theory bears some formal resemblance to the non-linear electrodynamics of Born and Infeld. A new interpretation is found for the Klotz–Russell skew-symmetric tensor.

The quasi-relativistic equations of Cowan and Griffin have been derived from the Dirac–Hartree–Fock theory. The one-electron integrals used in both methods are examined and a close relationship between them is established. It is argued that using nonorthogonal orbitals within the quasi-relativistic Hartree-Fock method is correct and in fact necessary.

We present new results on the production of hadron jets and of Intermediate Vector Bosons at the CERN \(\bar pp\) Collider at \(\sqrt {s}= 630\) GeV. Comparisons are made with data previously collected at \(\sqrt {s}= 546\) GeV, and with theoretical predictions from QCD and the Standard Model of the electroweak interaction.

Using the full data sample (\(\int {\cal {L}}dt = 310\) nb\(^{-1}\)) collected during the 1984 \(\bar pp\) Collider run (\(\sqrt {s}= 630\) GeV), the UA2 Collaboration has carried out a search for monojets and monophotons, as well as for multijet events with large missing transverse momentum (\(\rlap {/}p_{\rm T}\)). No significant signal could be isolated from background for either event type. The relevance of this result with respect to SUSY models is discussed. The method has been checked by, measuring the process \(\bar pp \to W+X\), \(W \to e\nu \) through a study of events with an electromagnetic cluster and large \(\rlap {/}p_{\rm T}\).

Following considerations about large \(N\) limit of QCD we propose to introduce a state dependent bag constant. We assume it is proportional to the number of constituents in a hadron. Numerical results for light hadron masses in the bag model support this suggestion.

We establish a formal correspondence between the Duffin–Kemmer–Petiau equation for a spin-0 or spin-1 particle and the Dirac equation for a spin-1/2 particle existing in four species. We hint at the possibility that any elementary Dirac particle appears necessarily in four such species (which might be identified with four fermionic generations).

The quark–antiquark plasma near equilibrium is studied. The results are based on the Heinz kinetic equations with the Boltzmann collision operator approximated by a relaxation term with the relaxation time, \(\tau \), treated as a small parameter. Linear in \(\tau \) solutions of these equations are used to calculate the transport coefficients: the non-abelian version of Ohm’s law and the shear and volume viscosities. We introduce new chemical potentials which determine the color density matrix of quarks (antiquarks). Gradients of these potentials generate color currents.

The electric charge of the vacuum around a magnetic monopole is calculated using fermionic states normalized in a spherical box of radius \(R \to \infty \). The results are compared with results of other authors, who used continuum normalization and with the results for one-dimensional chiral bags. New components of the charge density, which are omitted in the continuum approach, are found.