vol. 40, p. 3 (11 pages)
•abstract
A study of non-static spherically symmetric space-times according to their proper affine vector fields is given by using holonomy and decomposability, the rank of the \(6\times 6\) Riemann matrix and direct integration techniques. It is shown that when the above space-times admit proper affine vector fields, they turn out to be static and spherically symmetric. In the non-static cases affine vector fields are just Killing vector fields.
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https://www.actaphys.uj.edu.pl/R/40/1/3/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/3
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Acta Phys. Pol. B 40, 3 (2009)
vol. 40, p. 15 (9 pages)
•abstract
The ground-state energy related to three particles subjected to a complex PT potential is calculated via the variational perturbation method for quantum statistical density matrices. It is found that the obtained energies are real and positive.
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https://www.actaphys.uj.edu.pl/R/40/1/15/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/15
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Acta Phys. Pol. B 40, 15 (2009)
vol. 40, p. 25 (16 pages)
•abstract
We propose wormholes solutions by assuming space dependent equation of state parameter. Our models show that the existence of wormholes is supported by phantom energy. Here, the phantom energy is characterized by variable equation state parameter. We show that the averaged null energy condition (ANEC) violating phantom energy can be reduced as desired.
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https://www.actaphys.uj.edu.pl/R/40/1/25/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/25
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Acta Phys. Pol. B 40, 25 (2009)
vol. 40, p. 41 (7 pages)
•abstract
The paper will show the direct connections between q-Malthusian growth model, i.e. the classical exponential growth model generalized in Tsallis statistics, and the coalition growth model introduced by von Foerster in \(1960\). As it will turn out, the equations that have been taken into account when the coalition model was introduced, are closely related to the equations that describe the non-extensive generalization of entropy.
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https://www.actaphys.uj.edu.pl/R/40/1/41/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/41
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Acta Phys. Pol. B 40, 41 (2009)
vol. 40, p. 49 (9 pages)
•abstract
We derive results for two constants of the motion of a one-dimensional damped harmonic oscillator with position-dependent frictional coefficient and use them to obtain two alternative Lagrangian representations, which are not connected by a gauge term. The Hamiltonians corresponding to these Lagrangians lead to canonically inequivalent phase-space descriptions. We could, however, make use of a perturbation theoretic approach to quantize the classical motion using both Hamiltonians and thus demonstrate that the corresponding quantum systems are entirely different.
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https://www.actaphys.uj.edu.pl/R/40/1/49/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/49
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Acta Phys. Pol. B 40, 49 (2009)
vol. 40, p. 59 (8 pages)
•abstract
We study weak solutions to the Klein–Gordon equation with the logarithmic nonlinearity on interval. Such kinds of nonlinearities appear in inflation cosmology and in supersymmetric field theories. Moreover, this framework is applied in nuclear physics, optics, and geophysics. We obtained the existence of weak solutions. For this purpose the Galerkin method, logarithmic Sobolev inequality and compactness theorem are applied.
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https://www.actaphys.uj.edu.pl/R/40/1/59/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/59
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Acta Phys. Pol. B 40, 59 (2009)
vol. 40, p. 67 (8 pages)
•abstract
We propose a scenario of dynamical electroweak symmetry breaking which is applicable to the model with no tree-level potential for the elementary Higgs doublet field. An example of such a model is the gauge-Higgs unification model. The strong coupling “technicolor” dynamics can provide the scale of the electroweak symmetry breaking in the potential of the Higgs doublet field. The negative mass squared and quartic coupling can be generated through the Yukawa couplings among heavy and light “technifermions” and the Higgs doublet field. Since the massless “technifermion” is singlet under the electroweak gauge symmetry, no large corrections to the electroweak observables arise. As a prediction of this scenario, there must be a pseudo-Nambu–Goldstone boson which couple with the Higgs field in a specific way, though it is singlet under the standard model gauge symmetry.
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https://www.actaphys.uj.edu.pl/R/40/1/67/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/67
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Acta Phys. Pol. B 40, 67 (2009)
vol. 40, p. 75 (18 pages)
•abstract
In this paper we describe a check of the implementation of SANC system generated modules into the framework of the WINHAC Monte Carlo event generator. At this stage of work we limit ourselves to inclusion of complete one-loop electroweak corrections to the charged-current Drell–Yan process. We perform tuned comparisons of the results derived with the aid of two codes: (1) the standard SANC integrator with YFS-inspired treatment of the ISR QED corrections and (2) the WINHAC generator, upgraded with the SANC electroweak modules and downgraded to the \(\cal O(\alpha )\) QED corrections. The aim of these comparisons is to prove the correctness of implementation of the SANC electroweak modules into the WINHAC generator. This is achieved through the presented tuned comparisons.
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https://www.actaphys.uj.edu.pl/R/40/1/75/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/75
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Acta Phys. Pol. B 40, 75 (2009)
vol. 40, p. 93 (17 pages)
•abstract
We study top–antitop pair production and top spin correlations in a model with an electrically neutral massive gauge boson, \(Z'\), at the Large Hadron Collider. In addition to the Standard Model processes, the \(Z'\) contributes to the top–antitop pair production process in the \(s\)-channel. Choosing a kinematical region of top invariant mass around the \(Z'\) resonance pole, we find sizable deviations of the top–antitop pair production cross-section and the top spin correlations from those of the Standard Model.
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https://www.actaphys.uj.edu.pl/R/40/1/93/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/93
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Acta Phys. Pol. B 40, 93 (2009)
vol. 40, p. 111 (12 pages)
•abstract
We describe more precisely the mechanism of spontaneous mass generation in the previously proposed model of hidden sector of the Universe. The hidden sector is conjectured to consist of sterile spin-1/2 fermions (sterinos) whose mass is spontaneously generated by sterile scalar bosons (sterons), while their interactions are mediated by sterile antisymmetric-tensor bosons (A bosons). Such a sector communicates with the familiar Standard Model sector through a photonic portal acting weakly between both sectors (but stronger than the universal gravity). This is due to photons which, beside sterinos and sterons, contribute to the source of the A bosons. Sterinos can be candidates for thermal cold dark matter. They can be also produced in sterino–antisterino pairs through virtual photons emitted in high-energy collisions of Standard Model charged particles. Sterinos display a tiny magnetic moment spontaneously generated by sterons.
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https://www.actaphys.uj.edu.pl/R/40/1/111/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/111
cite as
Acta Phys. Pol. B 40, 111 (2009)
vol. 40, p. 123 (29 pages)
•abstract
We apply the non-local chiral quark model to study vector and axial pion-to-photon transition amplitudes that are needed as a nonperturbative input to estimate the cross-section of pion annihilation into the real and virtual photon. We use a simple form of the non-locality that allows to perform all calculations in the Minkowski space and guaranties polynomiality of the TDAs. We note only residual dependence on the precise form of the cut-off function, however vector TDA that is symmetric in skewedness parameter in the local quark model is no longer symmetric in the non-local case. We calculate also the transition form-factors and compare them with existing experimental parametrizations.
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https://www.actaphys.uj.edu.pl/R/40/1/123/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/123
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Acta Phys. Pol. B 40, 123 (2009)
all authors
A.G. Artukh, A. Budzanowski, G. Kamiński, W. Kantor, S.A. Klygin, E. Kozik, Yu.M. Sereda, J. Szmider, Yu.G. Teterev, A.N. Vorontzow
vol. 40, p. 153 (11 pages)
•abstract
The charge and relative velocity distributions of forward emitted fragments in the \(^{22}\)Ne + \(^{9}\)Be reaction at bombarding energy of 40 \(A\)MeV are presented. Experimental results are compared with the quantum molecular dynamics (QMD) model taking into account in calculations the mean field-like effects and the two-body scattering term. In the theoretical analysis a subsequent statistical decay of excited primary reaction products following the QMD predictions is applied. The assumption of two scenarios responsible for production of forward emitted fragments results in a good representation of the data suggesting a preferential contribution of the mean field-like effects in production mechanism.
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https://www.actaphys.uj.edu.pl/R/40/1/153/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/153
cite as
Acta Phys. Pol. B 40, 153 (2009)
vol. 40, p. 165 (10 pages)
•abstract
A mean field calculation is carried out to obtain the equation of state (EoS) of nuclear matter from a density dependent M3Y interaction (DDM3Y). The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of the symmetric nuclear matter (SNM). In this work, the energy variation of the exchange potential is treated properly in the negative energy domain of nuclear matter in contrast to an earlier work where it was assumed to vary negligibly inside nuclear fluid. The EoS of SNM, thus obtained, is not only free from the superluminosity problem but also provides good estimate of nuclear incompressibility. The DDM3Y, whose density dependence is determined from nuclear matter calculation, provides excellent description for proton radioactivity.
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https://www.actaphys.uj.edu.pl/R/40/1/165/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/165
cite as
Acta Phys. Pol. B 40, 165 (2009)
vol. 40, p. 175 (20 pages)
•abstract
We investigate topology and temporal evolution of the foreign currency exchange market viewed from a weighted network perspective. Based on exchange rates for a set of 46 currencies (including precious metals), we construct different representations of the FX network depending on a choice of the base currency. Our results show that the network structure is not stable in time, but there are main clusters of currencies, which persist for a long period of time despite the fact that their size and content are variable. We find a long-term trend in the network’s evolution which affects the USD and EUR nodes. In all the network representations, the USD node gradually loses its centrality, while, on contrary, the EUR node has become slightly more central than it used to be in its early years. Despite this directional trend, the overall evolution of the network is noisy.
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https://www.actaphys.uj.edu.pl/R/40/1/175/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/175
cite as
Acta Phys. Pol. B 40, 175 (2009)
vol. 40, p. 195 (11 pages)
•abstract
Effects of the neutrino trapping and symmetry energy behavior are investigated in the framework of the chiral Kaplan–Nelson model with kaon condensation. Decrease in the condensation threshold during deleptonization if found to be generic regardless uncertainties in the nucleon–kaon interactions and symmetry energy. Quantitatively however, differences are shown to be important.
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https://www.actaphys.uj.edu.pl/R/40/1/195/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/195
cite as
Acta Phys. Pol. B 40, 195 (2009)
vol. 40, p. 207 (5 pages)
•abstract
The vacuum equations for Bianchi I cosmology in the conformal Poincaré-gauge theory of gravitation are considered. All possible cases are investigated. It is shown that do not exist the solutions which are different from the Kasner line element.
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https://www.actaphys.uj.edu.pl/R/40/1/207/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/207
cite as
Acta Phys. Pol. B 40, 207 (2009)
ERRATUM for Acta Phys. Pol. B 39, 115 (2008)
vol. 40, p. 213 (1 page)
direct link to the full text (pdf)
https://www.actaphys.uj.edu.pl/R/40/1/213/pdf
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https://www.actaphys.uj.edu.pl/R/40/1/213
cite as
Acta Phys. Pol. B 40, 213 (2009)
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