5,896 research outputs found
Four fermion final states in annihilation
The present status of calculations of four fermion final states is reviewed.
Higher order problems arising there are pointed out. Special attention is paid
to results obtained in the semi-analytical approach and their limitations and
perspectives.Comment: 10 pages latex, uses nuclphys.sty (included), 1 figure included by
epsf.sty, invited talk held at ``QED and QCD at higher orders'', Rheinsberg,
April 199
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
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
Predictions for Fermion Pair Production at e+e- Colliders
We discuss the status and some ongoing upgrades of the ZFITTER program for
applications at e+e- colliders LEP1/SLC, LEP2, GigaZ, and TESLA. The inclusion
of top quark pair production is under work.Comment: 10 pages, 1 table, 2 figures, uses npb.sty, to appear in the
proceedings of Zeuthen Workshop: Loops and Legs in Quantum Field Theory, 9-14
April, Bastei, German
GENTLE/4fan v.2.0 - A Program for the Semi-Analytic Calculation of Predictions for the Process e+e- -> 4f
We describe version 2.0 of the Fortran program GENTLE/4fan for the
semi-analytic computation of cross-sections and distributions in four-fermion
production in e+e- annihilation. GENTLE/4fan covers all charged current and
neutral current our-fermion final states with no identical particles, no
electrons, and no electron neutrinos in the final state. Initial state
radiation representing the most relevant quantum corrections and anomalous
triple gauge boson couplings have been included.Comment: 38 pages, LaTex, 4 tables, uses fleqn.sty and elsart.cl
Radiative corrections to e+e- --> WW --> 4f with RACOONWW
RACOONWW is the first Monte Carlo generator for e+e- --> WW --> 4f(+gamma)
that includes the electroweak O(alpha) radiative corrections in the double-pole
approximation completely. Some numerical results for LEP2 energies are
discussed, and the predictions for the total W-pair cross section are
confronted with LEP2 data.Comment: 7 pages, latex, 5 postscript files, to appear in the Proceedings of
the 5th Zeuthen Workshop on Elementary Particle Theory ``Loops and Legs in
Quantum Field Theory'', Bastei/Koenigstein, Germany, April 9-14, 200
Finite-width effects in the near-threshold ZZZ and ZWW production at ILC
We calculate the cross-section of the near-threshold off-shell and
production at the International Linear Collider taking into account
their instability and the principal part of NLO corrections. The calculations
are performed in the framework of the model of unstable particles with smeared
mass-shell. We show that the contribution of the finite and widths
(their instability) is large in the Higgs resonance range and should be taken
into account in the Higgs boson searches at future colliders.Comment: 5 pages, 6 figure
ZFITTER: a semi-analytical program for fermion pair production in e+e- annihilation, from version 6.21 to version 6.42
ZFITTER is a Fortran program for the calculation of fermion pair production
and radiative corrections at high energy e+e- colliders; it is also suitable
for other applications where electroweak radiative corrections appear. ZFITTER
is based on a semi-analytical approach to the calculation of radiative
corrections in the Standard Model. We present a summary of new features of the
ZFITTER program version 6.42 compared to version 6.21. The most important
additions are: (i) some higher-order QED corrections to fermion pair
production, (ii) electroweak one-loop corrections to atomic parity violation,
(iii) electroweak one-loop corrections to nu-e nu-e-bar production, (iv)
electroweak two-loop corrections to the W boson mass and the effective weak
mixing angle.Comment: 60 pages, latex, 3 table
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