### Regular Series

#### Vol. 21 (1990), No. 12, pp. 929 – 1048

Static, Cylindrically Symmetric Solution of the Generalized Field Equations

Acta Phys. Pol. B 21, 929 (1990)

page 929 •

abstract

The problem of finding cylindrically symmetric static solutions of the Generalized Field Theory is completely solved. The electromagnetic fields are shown to vanish faster with the distance from the axis of symmetry than the corresponding curvature of the associated space-time. On the other hand, when the latter becomes a flat Minkowski manifold, the symmetric field is zero but the theory predicts exactly the Maxwellian electric and magnetic fields.

Ambiguities and Problems in Higher Order Corrections

Acta Phys. Pol. B 21, 947 (1990)

page 947 •

abstract

The formalism of optimization of perturbative higher order corrections with respect to the renormalization scales is extended to include the factorization scales. We consider the most general case with massless as well as massive particles. As a test of the optimization procedure, we apply our results to the recent O($\alpha ^3_s$) calculation of the ratio $R_{\rm e^+e^-} = \sigma _{\rm tot}$ (e$^+$e$^- \to$ hadrons)/$\sigma$(e$^+$e$^- \to \mu ^+ \mu ^-$), energy–energy correlation function and large $P_{\rm t}$ direct photon production in proton-antiproton inelastic collision. We conclude that the optimal scales give always a bit larger result and in some cases, the difference with respect to the physical scales is considerable.

Multiplicity and Transverse Energy Distributions in p $+ A$ and $A + A$ Collisions

Acta Phys. Pol. B 21, 969 (1990)

page 969 •

abstract

Multiplicity and transverse energy distributions in the midrapidity region in p + nucleus and nucleus + nucleus collisions are reconstructed on the basis of independent nucleon + nucleon interactions in wide range of beam energies.

Looking for Super Symmetry Signals in “Neutrino–Electron Scattering”

Acta Phys. Pol. B 21, 977 (1990)

page 977 •

abstract

The processes sneutrino–electron scattering and photino–electron scattering are considered. The expressions for the recoil electron energy distribution and the longitudinal polarization asymmetry are given and these are different from the corresponding expression for the neutrino–electron scattering. Hence detailed study of these observables is suggested as a test for “contamination” of light super symmetric particles in a neutrino beam.

On Instanton-Induced Effective Action

Acta Phys. Pol. B 21, 985 (1990)

page 985 •

abstract

A four-quark model motivated by determinant ’t Hooft interaction for the case of SU(2) $\otimes$ SU(2)r symmetry is investigated. Using the method of functional integration, meson fields are introduced and the perturbation theory based on expansion in loops is considered. It is shown that a dynamic symmetry breaking takes place in the model; the role of Goldstone bosons is played by $\pi$-mesons. A constituent quark mass dependence on the quark condensate and a dimensional coupling constant (associated with the instanton density) dependence on the momentum-cutoff, whose inverse value gives the instanton size, have been obtained. At the momentum-cutoff of ${\mit \Lambda } =$ 1 GeV and current mass of quarks $m_0 =$ 5 MeV experimental values of the $\pi$-mesons mass, quark condensate and dynamic quark mass have been reproduced. Completely effective action describing the interaction of mesons has been derived within the framework of the proposed model.

Effects of the Structure of Photon in Deep Inelastic Compton Process at HERA

Acta Phys. Pol. B 21, 999 (1990)

page 999 •

abstract

We investigate the deep inelastic Compton process $\gamma {\rm p} \Rightarrow \gamma$X at the forthcoming ep collider HERA ($\sqrt {s_{\gamma {\rm p}}} \sim 170$ GeV). We perform the consistent, order $\alpha ^2\alpha _s$ calculation of the DIC cross section paying particular attention to the contributions which appear due to the hadron-like interaction of photon. In addition we include new important higher order contributions, $\sim \alpha ^2\alpha _s^2$, which arise due to the hadronic nature of initial and final photons. We find that the production of photons with transverse momenta $p_{\rm T}$ up to $\sim 15$ GeV/c is dominated by events involving hadron-like interactlot of photon, with a significant contribution from the new subprocesscs. In this region of $p_{\rm T}$ there appears an interesting poesibility to probe separately the content of gluons in photon and in proton as they contribute to the different domains of rapidity.

Intermittency Analysis of Correlated Data

Acta Phys. Pol. B 21, 1021 (1990)

page 1021 •

abstract

In this report we describe the method of the analysis of the dependence of the factorial moments on the bin size in which the correlations between the moments computed for different bin sizes arc taken into account. For large multiplicity nucleus–nucleus data inclusion of the correlations does not change the values of the slope parameter, but gives errors significantly reduced as compared to the case of fits with no correlations.

Elastic Scattering of $^4$He by $^{12}$C at 96.6 MeV

Acta Phys. Pol. B 21, 1031 (1990)

page 1031 •

abstract

Differential cross section for the $^4$He–$^{12}$C elastic scattering at 96.6 MeV is reported. The data taken as well as existing data at 104 and 139 MeV arc found to be well described by using the scattering-matrix formalism with a model-free determination of the real part of the nuclear phase-shift. The variation of the rainbow angle with energy is discussed.

The Isospin-Forbidden ${\frac {5^-}{2}} \to {\frac {5^-}{2}}$ $\beta$-Transition of $^{65}$Ni

Acta Phys. Pol. B 21, 1037 (1990)

page 1037 •

abstract

The asymmetry parameter has been obtained from experiments on the $\frac {5^-}{2} \overset {\beta ^-}{\rightarrow } \frac {5^-}{2} \overset {\beta ^-}{\rightarrow } \frac {3^-}{2}$ circular polarization correlation measurements for the $\beta ^-$ decay of $^{65}$Ni. From this, a value for the Fermi nuclear matrix element $M_{\rm F}$ can be deduced. However, in this case, $M_{\rm F}$ is dependent on the value of the E2/M1 mixing amplitudes $\delta$ for the $\frac {5^-}{2}$ 1116-keV to the $\frac {3^-}{2}$ ground-state $\gamma$ transition. Our calculation yields a value of $|M_{\rm F}| = 1.85 \times 10^{-3}$ which is in reasonable agreement with the experimental $|M_{\rm F}| = 1.6 \times 10^{-3}$ if the E2/Ml mixing amplitude is measured using the technique of angular distribution of $\gamma$ rays following Coulomb excitation.

full authors' list

Yu.P. Gangarskyi, Khr.G. Khristov, F.G. Kondev, A.P. Tonchew, A.D. Antonov, N.P. Balabanov, S.G. Marinova, V.J. Tcholakov

The Excitation Function of the $^{65}$Cu($\gamma , \alpha$) $^{61}$Co Reaction in the Giant Resonance Region

Acta Phys. Pol. B 21, 1041 (1990)

page 1041 •

abstract

The $^{65}$Cu($\gamma , \alpha )^{61}$Co reaction has been studied using induced radioactivity techniques at gamma-ray energies of 25 MeV. The cross section has a maximum value of 1.20 $\pm$ 0.24 mb. at the energy of 22.0 $\pm$ 0.4 MeV and an integrated cross section at 25 MeV is 7.8 $\pm$ 2.3 MeV mb. The statistical model gives a satisfactory interpretation of the cross section ratio of the $^{65}$Cu($\gamma , \alpha )^{61}$Co and $^{65}$Cu($\gamma , {\rm n})^{64}$Cu reactions.

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