Exploitable results
In this project, the participants will extend their previous results, to find compact theoretical expressions for one loop radiative corrections of Electroweak theory to different physical observables at LEP and at future colliders. Comparing them with experimental data one can, in principle, obtain not only the bounds on the top quark and Higgs boson masses (on mt and Mh) but also understand the status of Electroweak theory. This project aims at understanding the connection of new experimental data on mt with information which follows (independently of Mh value) from theory of B-meson decays and Bº - `Bº oscillations. For that aim, the theory of B-decays, in particular to multihadron final states, was revised. Non-perturbative QCD wave function of B-meson will be used and also small QCD corrections will be considered. About 20% of the so-called internal inclusive non-leptonic B-decays into heavy mesons and in baryon pairs (previously lost) were found. In this approach the participants plan to calculate all decay main branchings and distributions. In connection with these problems a new model of unification approach (so-called anti-grand unification) is being developed and the phase transitions with a change to the internal symmetry are being considered. Values of gauge coupling (i.e. of the fine structure) constants will be studied in the vicinity of the multicritical point. The role of Higgs scalars, of monopoles, strings and fermions in this new approach will also be investigated.
The following problems were considered and discussed in 66 publications:
1.The research activity was devoted to different aspects of radiative corrections to intermediate vector bosons properties manifestations. Among other results it is necessary to stress the global fit of electroweak data which takes into account leading supersymmetric corrections.
2.In the supersymmetry (SUSY) and supergravity (SUGRA) theories a simple method for the diagonalisation of an n x n hierarchical mass matrix was suggested and used for the investigation of the Minimal SUSY Standard Model (MSSM) and the Next to Minimal such model (NMSSM). Simple expression for Higgs boson mass spectra in both these models were obtained in analytic form.
3.The eminent achievement was a "generalised factorisation" - a new method to include non-facotrizable contributions to nonleptonic decays. This method is now widely applied by many authors in particular for the elevation of B decays to light mesons. Also the eta-eta' mixing problem and the charm content of the eta- meson were investigated.
4.The connection between heavy (e.g. b, c or s) quark decay rates in the free state and bound inside mesons or hyperons was established. It has the simplest form in the constituent quark model formulated on the light cone, with the used of a nonperturbative wave function for the internal motion of the decaying meson. The form-factors for a number of exclusive weak transitions of heavy mesons were calculated and the accuracy of the factorisation approximation for the nonleptonic decays of heavy mesons was investigated. Review papers on decays of these mesons were published.
5.The Multiple Point Principle (MPP) asserts that physical parameters tend to have fine-tuned values corresponding to the junction of all possible "phases" in a generalised action parameter space. Together with the Anti-Grand Unified Theory (AGUT) gauge group, the MPP yields remarkably good predictions of the three gauge coupling constants and gives at least approximately correct values of virtually all Standard Model free parameters. The MPP implies a phenomenlogically acceptable form of long range non-locality that is inextricably related to a MPP based model for the fine-tuning of physical quantities.
6.The investigation of the quark-lepton mass hierarchy problem was developed within AGUT, assuming the fundamental Yukawa couplings are all of order unity at the Planck scale. A successful fit to the charged fermion spectrum was obtained.
7.The phase transition phenomena and the role of the monopoles were investigate in gauge theories. The different regularisation schemes were considered in the AGUT. The approximate "universality" (regularisation independence) of critical coupling constants was established.
8.The evolution of running QCD constant αs (µ) was computed in the 4-loop approximation of the Gell-Mann-Low β-function. The value of gluon condensate was estimated.
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