100 research outputs found
Color dielectric model with two scalar fields
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
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)
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
Venture Capital and Business Angels and the Creation of Innovative Firms in Poland
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
The interaction between kink and radiation in nonlinear one-dimensional real
scalar field is investigated. The process of discrete vibrational mode
excitation in 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
Gospodarka światowa w dobie globalizacji
Praca recenzowana / peer-reviewed pape
High temperatures and absence of light affect the hatching of resting eggs of Daphnia in the tropics
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