arXiv subjects
Publications and source records attributed to A. V. Bogdan.
This paper is devoted to the calculation of the Reggeized quark-Reggeized quark-gluon effective vertex in perturbative QCD in the next-to-leading order. The case of QCD with massless quarks is considered and the correction is obtained in the D->4 limit. This vertex appears in the quark Reggeization theory, which next-to-leading order extension is now under construction.
The two-loop quark Regge trajectory is obtained at arbitrary space-time dimension D using the s-channel unitarity conditions. Although explicit calculations are performed for massless quarks, the method used allows to find the trajectory for massive quarks as well. At D->4 the trajectory turns into one derived earlier from the high-energy limit of the two-loop amplitude for the quark-gluon scattering. The comparison of two expressions, obtained by quite different methods, serves as a strict cross check of many intermediate results used in the calculations, and their agreement gives a strong evidence of accuracy of these results.
The compatibility of the multi--Regge form of QCD amplitudes in the quasi--multi--Regge kinematics (QMRK) and the s--channel unitarity imposes some constraints on the effective jet--production vertices. We demonstrate that these constraints known as bootstrap conditions are satisfied for the amplitudes with the Reggeized quark exchanges.
In frames of agreement to consider the annihilation of electron-positron pair to hadrons cross section to be including the virtual photon polarization effects a new formulation of hadron contribution to muon anomalous magnetic moment is suggested. It consists in using the experimentally observed cross section converted with the known kernels. The lowest order kernel remains to be the same but some modification of radiative corrected kernel is needed. The explicit form of this new kernel is given. We estimate the accuracy of new formulation on the level δa^{hadr}_μ/a^{hadr}_μ\sim 10^{-5}.
A complete proof of the quark Reggeization hypothesis in the leading logarithmic approximation for any quark--gluon inelastic process in the multi--Regge kinematics in all orders of $α_s$ is given. First, we show that the multi--Regge form of QCD amplitudes is guarantied if a set of conditions on the Reggeon vertices and the trajectories is fulfilled. Then, we examine these conditions and show that they are satisfied.
New method of calculation of master integrals using differential equations and asymptotical expansion is presented. This method leads to the results exact in space-time dimension $D$ having the form of the convergent power series. As an application of this method, we calculate the two--loop master integral for "crossed--triangle" topology which was previously known only up to $O(\ep)$ order. The case when a topology contains several master integrals is also considered. We present an algorithm of the term-by-term calculation of the asymptotical expansion in this case and analyze in detail the "crossed--box" topology with three master integrals.
The updated results of the precise measurements of the processes e+e-->rho->pi+pi-, e+e-->omega->pi+pi-pi0 and e+e-->phi->KLKS performed by the CMD-2 collaboration are presented. The update appeared necessary due an overestimate of the integrated luminosity in previous analyses.
The hypothesis of the quark Reggeization is tested by taking the high-energy limit of the two-loop amplitude for quark-gluon scattering which was recently calculated. The limit is compatible with the Reggeization in the leading and the next-to-leading orders and allows the determination of the quark trajectory in the two-loop approximation. The trajectory is presented as an expansion in powers of (D-4) for the space-time dimension $D$ tending to the physical value D=4.