5,956 research outputs found
One loop light-cone QCD, effective action for reggeized gluons and QCD RFT calculus
The effective action for reggeized gluons is based on the gluodynamic
Yang-Mills Lagrangian with external current for longitudinal gluons added, see
[1]. On the base of classical solutions, obtained in [2], the one-loop
corrections to this effective action in light-cone gauge are calculated. The
RFT calculus for reggeized gluons similarly to the RFT introduced in [3] is
proposed and discussed. The correctness of the results is verified by
calculation of the propagator of and reggeized gluons fields
and application of the obtained results is discussed as well.Comment: 24 page
On the application of the effective action approach to amplitudes with reggeon splitting
Application of the effective action approach to amplitudes with loop
integration is studied for collisions on two and three centers with possible
gluon emission. A rule is formulated for the integration around pole
singularities in the induced vertices which brings the results in agreement
with the QCD. It is demonstrated that the amplitudes can be restored from the
purely transverse picture by introducing the standard Feynman propagators for
intermediate gluons and quarks.Comment: 16 pages, 9 figures; submitted to Eur.Phys.Jour.
Diffractive scattering on the deuteron projectile in the NLO: triple interaction of reggeized gluons
High-mass diffractive production of protons on the deuteron target is studied
in the next-to-leading order (NLO) of the perturbative QCD in the BFKL
approach. The non-trivial part of the NLO contributions coming from the triple
interactions of the exchanged reggeons is considered. Analytic formulas are
presented and shown to be infrared free and so ready for practical calculation.Comment: 28 pages, 2 figures; to be published in Eur.Phys.Jour.
Inverse Compton scattering in mildly relativistic plasma
We investigated the effect of inverse Compton scattering in mildly
relativistic static and moving plasmas with low optical depth using Monte Carlo
simulations, and calculated the Sunyaev-Zel'dovich effect in the cosmic
background radiation. Our semi-analytic method is based on a separation of
photon diffusion in frequency and real space. We use Monte Carlo simulation to
derive the intensity and frequency of the scattered photons for a monochromatic
incoming radiation. The outgoing spectrum is determined by integrating over the
spectrum of the incoming radiation using the intensity to determine the correct
weight. This method makes it possible to study the emerging radiation as a
function of frequency and direction. As a first application we have studied the
effects of finite optical depth and gas infall on the Sunyaev-Zel'dovich effect
(not possible with the extended Kompaneets equation) and discuss the parameter
range in which the Boltzmann equation and its expansions can be used. For high
temperature clusters ( keV) relativistic corrections based
on a fifth order expansion of the extended Kompaneets equation seriously
underestimate the Sunyaev-Zel'dovich effect at high frequencies. The
contribution from plasma infall is less important for reasonable velocities. We
give a convenient analytical expression for the dependence of the cross-over
frequency on temperature, optical depth, and gas infall speed. Optical depth
effects are often more important than relativistic corrections, and should be
taken into account for high-precision work, but are smaller than the typical
kinematic effect from cluster radial velocities.Comment: LateX, 30 pages and 11 figures. Accepted for publication in the
Astrophysical Journa
Unifying approaches: BK equation from the Lipatov's effective action
We consider a direct derivation of the Balitsky-Kovchegov
equation~\cite{Bal,Kovch} from the Lipatov's effective action~\cite{LipatovEff}
formulated in terms of interacting ordered exponentials~\cite{OurZub}. We
discuss the way the sub-leading eikonal corrections to the Balitsky-Kovchegov
equation arise from the transverse field contribution and sub-leading eikonal
corrections to the quark propagator. We outline other possible applications of
the proposed calculation scheme.Comment: 22 page
Wien Fireball Model of Relativistic Outflows in Active Galactic Nuclei
We study steady and spherically symmetric outflows of pure electron-positron
pair plasma as a possible acceleration mechanism of relativistic jets up to the
bulk Lorentz factor of greater than 10. These outflows are initiated by the
``Wien fireball'', which is optically thick to Compton scattering but thin to
absorption and in a Wien equilibrium state between pairs and photons at a
relativistic temperature.Comment: 16 pages, 13 figures, 1 table, ApJ in pres
Evolution of the Low-Energy Photon Spectra in Gamma-Ray Bursts
We report evidence that the asymptotic low-energy power law slope alpha
(below the spectral break) of BATSE gamma-ray burst photon spectra evolves with
time rather than remaining constant. We find a high degree of positive
correlation exists between the time-resolved spectral break energy E_pk and
alpha. In samples of 18 "hard-to-soft" and 12 "tracking" pulses, evolution of
alpha was found to correlate with that of the spectral break energy E_pk at the
99.7% and 98% confidence levels respectively. We also find that in the flux
rise phase of "hard-to-soft" pulses, the mean value of alpha is often positive
and in some bursts the maximum value of alpha is consistent with a value > +1.
BATSE burst 3B 910927, for example, has a alpha_max equal to 1.6 +/- 0.3. These
findings challenge GRB spectral models in which alpha must be negative of
remain constant.Comment: 12 pages (including 6 figures), accepted to Ap
Influence of scattering processes on electron quantum states in nanowires
In the framework of quantum perturbation theory the self-consistent method of calculation of electron scattering rates in nanowires with the one-dimensional electron gas in the quantum limit is worked out. The developed method allows both the collisional broadening and the quantum correlations between scattering events to be taken into account. It is an alternativeper seto the Fock approximation for the self-energy approach based on Green’s function formalism. However this approach is free of mathematical difficulties typical to the Fock approximation. Moreover, the developed method is simpler than the Fock approximation from the computational point of view. Using the approximation of stable one-particle quantum states it is proved that the electron scattering processes determine the dependence of electron energy versus its wave vector
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