6,246 research outputs found
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
An electroweak library for the calculation of EWRC to e+ e- --> f fbar within the CalcPHEP project
We present a description of calculations of the electroweak amplitude for e+
e- --> f fbar process. The calculations are done within the OMS (on-mass-shell)
renormalization scheme in two gauges: in Rxi, which allows an explicit control
of gauge invariance by examining cancellation of gauge parameters and search
for gauge-invariant subsets of diagrams, and in the unitary gauge as a
cross-check. The formulae we derived are realized in a FORTRAN code eeffLib,
which is being created within the framework of the project CalcPHEP. We present
a comprehensive comparison between eeffLib results for the light top with
corresponding results of the well-known program ZFITTER for the u ubar channel,
as well as a preliminary comparison with results existing in the world
literature.Comment: Revised version, 47 Latex, including 14 figures (2 eps figures), 5
table
J_AW,WA functions in Passarino-Veltman reduction
In this paper we continue to study a special class of Passarino-Veltman
functions J arising at the reduction of infrared divergent box diagrams. We
describe a procedure of separation of two types of singularities, infrared and
mass singularities, which are absorbed in simple C0 functions. The infrared
divergences of C0's can be regularized then by any method: photon mass,
dimensionally or by the width of an unstable particle. Functions J, in turn,
are represented as certain linear combinations of the standard D0 and C0
Passarino-Veltman functions. The former are free of both types of singularities
and are expressed as explicit and compact linear combinations of logarithms and
dilogarithm functions. We present extensive comparisons of numerical results
with those obtained with the aid of the LoopTools package
ZFITTER v.6.21 - A Semi-Analytical Program for Fermion Pair Production in e+e- Annihilation
We describe ZFITTER, a Fortran program based on a semi-analytical approach to
fermion pair production in e+e- annihilation at a wide range of centre-of-mass
energies, including the PETRA, TRISTAN, LEP1/SLC, and LEP2 energies. A flexible
treatment of complete O(alpha) QED corrections and of some higher order
contributions is made possible with three calculational chains containing
different realistic sets of restrictions in the photon phase space. Numerical
integrations are at most one-dimensional. Complete O(alpha) weak loop
corrections supplemented by selected higher-order terms may be included. The
program calculates Delta r, the Z width, differential cross-sections, total
cross-sections, integrated forward-backward asymmetries, left-right
asymmetries, and for tau pair production also final-state polarization effects.
Various interfaces allow fits to be performed with different sets of free
parameters.Comment: 200 pages, Latex2e, 26 figures, 4 tables; uses axodraw, epsfig, epsf,
graphicx, espcrc1; typos of v.1 corrected, version for subm. to Comp. Phys.
Commu
Atomic Parity-Violation and Precision Physics
The atomic parity-violation (APV) parameter QW for a nucleus with `n'
neutrons and `z' protons has been included in the list of pseudo-observables
accessible with the codes TOPAZ0 and ZFITTER. In this way one can add the APV
results in the LEP EWWG `global' electroweak fits, checking the corresponding
effect when added to the existing precision measurements.Comment: 9 Late
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