The experimental information comes from three sectors: the very high precision Z boson measurements at LEP 1 and the SLC; direct mass measurements and constraints from the Tevatron and LEP 2; and low energy precision experiments, such as in atomic parity violation, deep inelastic scattering, and rare decays. These measurements are compared with the predictions of the SM and its extensions. The level of precision is generally very high. Leading and subleading two loop electroweak results have been included in our analysis. Mixed electroweak/QCD calculations up to four loop order are required, and in some cases it is necessary to estimate gluonic or photonic five loop effects. It is also important to utilize efficient renormalization schemes and scales to assure sufficient convergence of the perturbative expansions. The high precision and the variety of observables involved in the project calls further for a consistent treatment of the input parameters in all processes. For example, the strong coupling constant and the charm and bottom quark masses enter directly into Z boson decays, but also indirectly in the renormalization group evolution of the electromagnetic coupling from the Thomson limit to the Z scale: since both are relevant for the determination of the Higgs boson mass, M_H, important correlations emerge and should be taken into account as parametric uncertainties.

The complexity of these problems called for the creation of a special purpose FORTRAN library, GAPP, short for the Global Analysis of Particle Properties. It is devoted to the calculation of pseudo-observables, i.e. observables with experiment specific corrections (such as initial state radiation or detector specifics) removed. The reduction of raw data to pseudo-observables is performed by the experimenters with available packages (e.g. ZFITTER for Z pole physics). GAPP attempts to gather all available theoretical and experimental information from precision measurements in particle physics; it allows the addition of extra parameters describing new physics; it treats all relevant SM inputs as global fit parameters; and it can easily be updated with new calculations, data, observables, or fit parameters. For clarity and to minimize CPU costs it avoids numerical integrations throughout. It is based on the modified minimal subtraction scheme which demonstrably avoids large expansion coefficients.

GAPP is endowed with the option to constrain the oblique parameters, which affect the gauge boson self-energies, and are called, e.g. S, T, and U. Similarly, the number of active neutrinos with standard couplings to the Z boson can be extracted, as well as specific Z couplings. Most recently, the ability to constrain additional Z bosons has been added. It is now possible to constrain the masses, mixings, and coupling strengths of any extra Z boson appearing in models of new physics.

With view on the importance of supersymmetric extensions of the SM on one hand, and upcoming experiments on the other, we also included the b -> s photon transition amplitude, and intend to add the muon anomalous magnetic moment. In the latter case, there are theoretical uncertainties from hadronic contributions which are partially correlated with the renormalization group evolutions of the QED coupling and the weak mixing angle. These correlations will be partially taken into account by including heavy quark effects in analytical form; see Phys. Rev. D59, 054008 (1999) for a first step in this direction. By comparing this scheme with more conventional ones, it will also be possible to isolate a certain type of QCD sum rule, and to rigorously determine the charm and bottom quark "running" masses with high precision.

If you are in a UNIX environment and like to download the new version GAPP_99.7, click with the right mouse button on the globe

To compile the standard routine, type make fit; to compile the routine for Higgs mass scans type make mh; and to create plots for models with extra Z bosons, type make zplot. Note, that the number of scan points can be set in mh.f, and that a scan takes typically between 10 and 20 minutes. A plot created with zplot takes many hours; thus for test runs one should reduce the number of scan points significantly (in zplotter.f).

Included in the GAPP package are some routines for the calculation of one loop diagrams from the package FF written by G.J. van Oldenborgh. Don't forget to acknowledge the effort to create these reliable routines:

G.J. van Oldenborgh and J.A.M. Vermaseren, Z. Phys. C46, 425 (1990);
G.J. van Oldenborgh, Comput. Phys. Commun. 66, 1 (1991).

Questions and suggestions are more than welcome. Just drop a line!

erler@fisica.unam.mx