Elsevier Science Home
Computer Physics Communications Program Library
Full text online from Science Direct
Programs in Physics & Physical Chemistry
CPC Home

[Licence| Download | New Version Template] acnt_v2_0.gz(127 Kbytes)
Manuscript Title: TOPAZ0 2.0 - A program for computing de-convoluted and realistic observables around the Z0 peak.
Authors: G. Montagna, O. Nicrosini, G. Passarino, F. Piccinini
Program title: TOPAZ0 2.0
Catalogue identifier: ACNT_v2_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 93(1996)120
Programming language: Fortran.
Computer: VAX 6410.
Operating system: VMS, UNIX.
RAM: 600K words
Word size: 32
Keywords: Particle physics, Elementary, E+ e- annihilation, Bhabha scattering, Lep, Z0 resonance, Electroweak, Extrapolated and Realistic experimental Set-up, Qcd corrections, Corrections qed, Pure weak corrections, Radiative corrections, Minimal standard model, De-convoluted, Realistic observables, Theoretical Uncertainties.
Classification: 11.5.

Nature of problem:
An accurate theoretical description of e+e- annihilation processes and of Bhabha scattering at the Z0 resonance is necessary in order to compare theoretical cross sections and asymmetries with the experimental ones as measured by the LEP collaborations. In particular a realistic theoretical description, i.e. a description in which the effects of experimental cuts, such as maximum acollinearity, energy or invariant mass and angular acceptance of the outgoing fermions, are taken into account, allows the comparison of the Minimal Standard Model predictions with experimental raw data, i.e. data corrected for detector efficiency but not for acceptance. The program takes into account all the corrections, pure weak, QED and QCD, which allow for such a realistic theoretical description.

Solution method:
Same as in the original program. A detailed description of the theoretical formulation and of a sample of physical results obtained can be found in [2].

Reasons for new version:
The new version gives the possibility of computing observables in an experimental set-up with different cuts on cross sections and asymmetries, according to the most recently published LEP data. Radiative corrections whose effect can become relevant in view of the present and foreseen experimental accuracy have been included. An option is added which allows an estimate to be made of the theoretical uncertainty associated with unknown higher-order radiative corrections of electroweak and QCD origin.

The theoretical formulation is specifically worked out for energies around the Z0 peak. Analytic formulas have been developed for an experimental set-up with symmetrical angular acceptance. Moreover the angular acceptance of the scattered antifermion has been assumed to be larger than the one of the scattered fermion. The prediction for Bhabha scattering is understood to be for the large-angle regime.

Unusual features:
Subroutines from the library of mathematical subprograms NAGLIB [1] for the numerical integrations are used in the program.

Running time:
Dependent on the required experimental set-up. As evaluator of observables in seven energy points, between 10 (extrapolated set-up) and 270 (realistic set-up) CPU seconds for HP-APOLLO 7000, corresponding to 100-2500 CPU seconds for VAX 6410. As estimator of the theoretical uncertainty, it requires about 5400 CPU seconds for HP-APOLLO 7000, for a single energy point.

[1] NAG Fortran Library Manual Mark 15 (Numerical Algorithms Group, Oxford, 1991).
[2] G. Montagna, O. Nicrosini, G. Passarino, F. Piccinini and R. Pittau, Nucl. Phys. B401 (1993) 3.