arXiv subjects

E. Uglov

Publications and source records attributed to E. Uglov.

6 recordsLinked to original sources

arXiv2017

SANC: the process $ γγ\rightarrow ZZ $

The implementation of the process $γγ\to ZZ$ at the one-loop level within {\tt SANC} system multi-channel approach is considered. The derived one-loop scalar form factors can be used for any cross channel after an appropriate permutation of their arguments -- Mandelstam variables $s,t,u$. To check of the correctness of the results we observe the independence of the scalar form factors on the gauge parameters and the validity of Ward identity (external photon transversality). We present the complete analytical results for the covariant and tensor structures and helicity amplitudes for this process. We make an extensive comparison of our analytical and numerical results with those existing in the literature.

hep-ph↗

arXiv2014

$J$ functions for the process ud$\to$WA

In this paper we present a description of the universal approach for analytic calculations for a certain class of $J$ functions for six topologies of the boxes for process $ud\rightarrow WA$. These functions $J$ arise at the reduction of infrared divergent box diagrams. The standard Passarino--Veltman reduction of four-point box diagram with an internal photon line connecting two external lines on the mass shell leads to infrared-divergent and mass-singular $D_0$ functions. In the system SANC a systematic procedure is adopted to separate both types of singularities into the simplest objects, namely $C_0$ functions. The functions $J$, in turn, are represented as certain linear combinations of the standard $D_0$ and $C_0$ functions. The subtracted $J$ functions are free of both types of singularities and are expressed as explicit and compact linear combinations of dilogarithm functions. We present extensive comparisons of numerical results of SANC with those obtained with the aid of the LoopTools package.

hep-ph↗

arXiv2013

SANC system and its applications for LHC

The {\tt SANC} computer system is aimed at support of analytic and numeric calculations for experiments at colliders. The system is reviewed briefly. Recent results on high-precision description of the Drell-Yan processes at the LHC are presented. Special attention is paid to the evaluation of higher order final-state QED corrections to the single $W$ and $Z$ boson production processes. A new Monte Carlo integrator {\tt mcsanc} suited for description of a series of high-energy physics processes at the one-loop precision level is presented.

hep-ph↗

arXiv2012

$Zγγγ\to 0$ processes in SANC

In this paper we describe the analytic and numerical evaluation of the $γγ\to γZ$ process cross section and the $Z\to γγγ$ decay rate within the SANC system multi-channel approach at the one-loop accuracy level with all masses taking into account. The corresponding package for numeric calculations is presented. For checking of the results correctness we make a comparison with other independent calculations.

hep-ph↗

arXiv2009

Standard Model light-by-light scattering in SANC: analytic and numeric evaluation

In this paper we describe the implementation of the SM process $γγ\toγγ$ through a fermion and boson loops into the framework of SANC system. The computations of this process takes into account non-zero mass of loop particles. We briefly describe additional precomputation modules used for calculation of massive box diagrams. We present the covariant and helicity amplitudes for this process, some particular cases of $D_0$ and $C_0$ Passarino--Veltman functions and also numerical results of corresponding SANC module evaluation. Whenever possible, we compare the results with those existing in the literature.

hep-ph↗

arXiv2006

Light-by-light scattering in SANC

In this paper we describe the implementation of the QED process $γγ\toγγ$ through a fermion loop into the framework of SANC system. The computations of this process takes into account non-zero mass of loop-fermion. We briefly describe additional precomputation modules used for calculation of massive fermion-box diagrams. We present the covariant and helicity amplitudes for this process and also some particular cases of $D_0$ and $C_0$ Passarino-Veltman functions. Whenever possible, we compare the results with those existing in the literature.

hep-ph↗