99 research outputs found

    Color dielectric model with two scalar fields

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    SU(2) Yang-Mills theory coupled in a non-minimal way to two scalar fields is discussed. For the massless scalar fields a family of finite energy solutions generated by an external, static electric charge is found. Additionally, there is a single solution which can be interpreted as confining one. Similar solutions have been obtained in the magnetic sector. In case of massive scalar fields the Coulomb problem is investigated. We find that asymptotic behavior of the fields can also, for some values of the parameter of the model, give confinement of the electric charge. Quite interesting one glueball--meson coupling gives the linear confining potential. Finally, it is shown that for one non-dynamical scalar field we derive the color dielectric generalization of the Pagels--Tomboulis model.Comment: 20 pages, LaTeX, Accepted for publication in Eur. Phys. J.

    Non-abelian color dielectric - towards the effective model of the low energy QCD

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    Lattice motivated triplet color scalar field theory is analyzed. We consider non-minimal as well as covariant derivative coupling with SU(2) gauge fields. Field configurations generated by external electric sources are presented. Moreover non-Abelian magnetic monopoles are found. Dependence on the spatial coordinates in the obtained solutions is identical as in the usual Abelian case. We show also that after a decomposition of the fields a modified Faddeev-Niemi action can be obtained. It contains explicit O(3) symmetry breaking term parameterized by the condensate of an isoscalar field. Due to that Goldstone bosons observed in the original Faddeev-Niemi model are removed.Comment: 19 page

    The electromagnetic dipole operator effect on B -> Xs gamma at O(alpha_s^2)

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    The flavor-changing electromagnetic dipole operator O_7 gives the dominant contribution to the B -> Xs gamma decay rate. We calculate two-loop QCD corrections to its matrix element together with the corresponding bremsstrahlung contributions. The optical theorem is applied, and the relevant imaginary parts of three-loop diagrams are computed following the lines of our recent t -> Xb W calculation. The complete result allows us to test the validity of the naive non-abelianization (NNA) approximation that has been previously applied to estimate the NNLO QCD correction to Gamma(B -> Xs gamma)/Gamma(B -> Xu e nu). When both decay widths are normalized to m^5_{b,R} in the same renormalization scheme R, the calculated O(alpha_s^2) correction is sizeable (~ 6%), and the NNA estimate is about 1/3 too large. On the other hand, when the ratio of the decay widths is written as S*(m_b(m_b)/m_{b,pole})^2, the calculated O(alpha_s^2) correction to S is at the level of 1% for both the complete and the NNA results.Comment: Corrected pi^2 terms in the description of intermediate steps in Section II. Final results unchange

    Determinants of RES implementation in Poland and the European Union

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    Venture Capital and Business Angels and the Creation of Innovative Firms in Poland

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    The article also points out that conditions fostering further development of the described types of entrepreneurship and innovation financing and a dynamic environment generating innovative capacity should be created.W artykule zasygnalizowano również potrzebę kreowania uwarunkowań sprzyjających rozwojowi opisanych form finansowania przedsiębiorczości, innowacyjności i dynamicznego otoczenia generującego zdolności innowacyjne

    Creation of Kink and Antikink Pairs Forced By Radiation

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    The interaction between kink and radiation in nonlinear one-dimensional real scalar field is investigated. The process of discrete vibrational mode excitation in ϕ4\phi^4 model is considered. The role of this oscillations in creation of kink and antikink is discussed. Numerical results are presented as well as some attempts of analytical explanations. An intriguing fractal structure in parameter space dividing regions with creation and without is also presented
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