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R. N. Rogalyov

Publications and source records attributed to R. N. Rogalyov.

28 records · Page 2Linked to original sources
arXiv2013

Gluon Propagators in 3D SU(2) Theory and Effects of Gribov Copies

Infrared behavior of the Landau gauge gluon propagators is studied numerically in the 3d SU(2) gauge theory on the lattice. A special accent is made on the study of Gribov copy effect. For this study we employ an efficient gauge-fixing algorithm and a large number of gauge copies (up to 280 copies per configuration). It is shown that, in the deep infrared region, the Gribov copy effects are very significant. Also we show that, in the infinite-volume limit, the zero-momentum value of the propagator does not vanish.

hep-lat↗
arXiv2010

Two-Loop Fermionic Integrals in Perturbation Theory on a Lattice

A comprehensive number of one-loop integrals in a theory with Wilson fermions at $r=1$ is computed using the Burgio-Caracciolo-Pelissetto algorithm. With the use of these results, the fermionic propagator in the coordinate representation is evaluated, thus making it possible to extend the Luscher-Weisz procedure for two-loop integrals to the fermionic case. Computations are performed with FORM and REDUCE packages.

hep-lat↗
arXiv2009

One-Loop Diagrams in Lattice QCD with Wilson Fermions

A comprehensive number of integrals emerging in one-loop computations in a gauge perturbation theory on the lattice with Wilson fermions at $r=1$ is computed using the Burgio--Caracciolo--Pelissetto algorithm and the FORM package. An explicit analytical form of the recursion relations needed for such computations is presented.

hep-lat↗
arXiv2005

Ultraviolet Behavior of the Gluon Propagator in the Maximal Abelian Gauge

The ultraviolet asymptotic behavior of the gluon propagator is evaluated in the maximal Abelian gauge in the SU(2) gauge theory on the basis of the renormalization-group improved perturbation theory at the one-loop level. Square-root singularities obtained in the Euclidean domain are attributed to artifacts of the one-loop approximation in the maximal Abelian gauge and the standard normalization condition for the propagator used in our study. It is argued that this gauge is essentially nonperturbative.

hep-ph↗
arXiv2002

Uses of Covariant Formalism for Analytical Computation of Feynman Diagrams with Massive Fermions

The bilinear combination of Dirac spinors $u(p_1,n_1)\bar u(p_2,n_2)$ is expressed in terms of Lorentz vectors in an explicit covariant form. The fact that the obtained expression involves only one auxiliary vector makes it very convenient for analytical computations with REDUCE (or FORM) package in the helicity formalism. The other advantage of the proposed formulas is that they are applicable to massive fermions as well as to massless fermions. The proposed approach is employed for the computation of one-loop Feynman diagrams and it is demonstrated that it considerably reduces the time of computations.

hep-ph↗
arXiv2002

A Possibility to Measure CP-Violating Effects in the Decay K --> mu nu gamma

It is argued that a precise measurement of the transverse component of the muon spin in the decay K --> mu nu gamma makes it possible to obtain more stringent limits on CP-violating parameters of the leptoquark, SUSY and left-right symmetric models. The results of the calculations of the CP-even transverse component of the muon spin in the decay K --> mu nu gamma due to the final-state electromagnetic interactions are presented. The weighted average of the transverse component of the muon spin comprises 2.3 times 10^{-4}.

hep-ph↗
arXiv2002

CP Violation in K-Meson Decays

This is a pedagogical review of some selected topics of CP and T violation in the decays of K mesons. Diagonalization of the quark mass matrix and the emergence of the complex phase in both the standard and the left--right symmetric models is considered in great detail. Prominence is given to a correct definition of the CP-violating quantities: $ε, ε'$ {\it etc.} (with due regard for the Wu--Yang phase convention) and to formulation of the time-reversal invariance criterion in the elementary particle physics. A particular attention has been concentrated on theoretical evaluation of the parameters $ε$ and $ε'$ and the CP- and T-violating asymmetries in the decays $K \to μνγ$ and $K \to 3π$.

hep-ph↗
arXiv2002

The Uses of Chiral Anomaly for Determination of the Number of Colors

The $N_c$-dependence of the vertices $PPPγ$, where $P$ is a pseudoscalar meson and $N_c$ is the number of colors, is analyzed with regard for the $N_c$-dependence of the quark charges. It is shown that the best processes for the determination of $N_c$ are the reactions $Kγ\to Kπ$ and $π^pmγ\toπ^\pmη$ as well as the decay $η\raπ^+π^-γ$. The measurement of the cross section $σ(π^-γ\raπ^-η)$ at the VES facility at the IHEP agrees with the value $N_c=3$.

hep-ph↗
arXiv1995

CORE 2.1 (COmpendium of RElations, Version 2.1)

The present CORE 2.1 (COmpendium of RElations, Version 2.1) contains various formulas and relations used in the practical calculations in the Standard Model. The properties of the Pauli, Dirac, Gell--Mann matrices, wave functions of free fermions and gauge bosons are considered. We present the full Lagrangian of the Standard Model and the corresponding Feynman rules. The method of the evaluation of the Feynman (loop) integrals and calculations in non-covariant gauges is considered. We discuss in brief the relativistic kinematic and present a large number of the matrix elements of the various processes in the Standard Model.

hep-ph↗