245 research outputs found
Comparison of SANC with KORALZ and PHOTOS
Using the SANC system we study the one-loop electroweak standard model
prediction, including virtual and real photon emissions, for the decays of
on-shell vector and scalar bosons B --> f anti-f (gamma), where B is a vector
boson, Z or W, or a Standard Model Higgs. The complete one-loop corrections and
exact photon emission matrix element are taken into account. For the
phase-space integration, the Monte Carlo technique is used. For Z decay the QED
part of the calculation is first cross-checked with the exact one-loop QED
prediction of KORALZ. For Higgs boson and W decays, a comparison is made with
the approximate QED calculation of PHOTOS Monte Carlo. This provides a useful
element for the evaluation of the theoretical uncertainty of PHOTOS, very
interesting for its application in ongoing LEP2 and future LC and LHC
phenomenology.Comment: Submitted to Acta Physica Polonica. 9 pages, 6 figure
Theoretical and probability analysis of frequency selective circuits
The deviations of the circuit characteristics from their nominal values are random quantities and appear as a result
of different destabilizing factors. With designing frequency selective circuits, two mutually connected problems are solved.
The one is a study on the possible variations of circuit characteristics with given probability indices for the instability of the
characteristics of their elements. The other is to synthesize the circuit and to determine the nominal parameters of its
elements considering the requirements for stability of its characteristics. Both problems are solved by the methods of the
theory of circuit sensitivity. The paper presents a new approach to theoretical probability analysis of the characteristics of
frequency selective circuits depending on the relative changes of their parameters
Project {\tt SANC} (former {\tt CalcPHEP}): Support of Analytic and Numeric calculations for experiments at Colliders
The project, aimed at the theoretical support of experiments at modern and
future accelerators -- TEVATRON, LHC, electron Linear Colliders (TESLA, NLC,
CLIC) and muon factories, is presented. Within this project a four-level
computer system is being created, which must automatically calculate, at the
one-loop precision level the pseudo- and realistic observables (decay rates and
event distributions) for more and more complicated processes of elementary
particle interaction, using the principle of knowledge storing.
It was already used for a recalculation of the EW radiative corrections for
Atomic Parity Violation [1] and complete one-loop corrections for the process
[2-4]; for the latter an, agreement up to 11 digits with
FeynArts and the other results is found. The version of {\tt SANC} that we
describe here is capable of automatically computing the decay rates and the
distributions for the decays in the one-loop
approximation.Comment: 3 Latex, Presented at ICHEP2002, Amsterdam, July 24-30, 2000;
Submitted to Proceeding
SANC integrator in the progress: QCD and EW contributions
Modules and packages for the one-loop calculations at partonic level
represent the first level of SANC output computer product. The next level
represents Monte Carlo integrator mcsanc, realizing fully differential hadron
level calculations (convolution with PDF) for the HEP processes at LHC. In this
paper we describe the implementation into the framework mcsanc first set of
processes: DY NC, DY CC, ff->HW(Z) and single top production. Both EW and QCD
NLO corrections are taken into account. A comparison of SANC results with those
existing in the world literature is given
News on PHOTOS Monte Carlo: gamma^* -> pi^+ pi^-(gamma) and K^\pm -> pi^+ pi^- e^\pm nu (gamma)
PHOTOS Monte Carlo is widely used for simulating QED effects in decay of
intermediate particles and resonances. It can be easily connected to other main
process generators. In this paper we consider decaying processes gamma^* ->
pi^+ pi^-(gamma) and K^\pm -> pi^+ pi^- e^\pm nu (gamma) in the framework of
Scalar QED. These two processes are interesting not only for the technical
aspect of PHOTOS Monte Carlo, but also for precision measurement of
alpha_{QED}(M_Z), g-2, as well as pi pi scattering lengths.Comment: 6 pages, 11 figures, proceedings of the PhiPsi09, Oct. 13-16, 2009,
Beijing, Chin
Standard SANC modules for NLO QCD Radiative Corrections to Single-top Production
It this paper we present the results obtained with the newly created Standard
SANC modules for calculation of the NLO QCD corrections to single top
production processes in s and t channels at the partonic level, as well as
top-decays. The main aim of these results is to prove the correct work of
modules. A comprehensive comparison with results of the CompHEP system is
given, where possible. These modules are intended to be used in Monte Carlo
generators for single top production processes at the LHC. As in our recent
paper, devoted to the electroweak corrections to these processes, we study the
regularization of the top-legs associated infrared divergences with aid of the
complex mass of the top quark. A comparison of QCD corrections with those
computed by the conventional method is presented both for top production and
decays. For s channel production we give an analytic proof of equivalence of
the two methods in the limit of low top width.Comment: 21 pages, 2 figures, 17 table
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