Opucem: a Library With Error Checking Mechanism for Computing Oblique Parameters

Abstract

After a brief review of the electroweak radiative corrections to gauge-boson self-energies, otherwise known as the direct and oblique corrections, a tool for calculation of the oblique parameters is presented. This tool, named OPUCEM, brings together formulas from multiple physics models and provides an error-checking machinery to improve reliability of numerical results. It also sets a novel example for an "open-formula" concept, which is an attempt to improve the reliability and reproducibility of computations in scientific publications by encouraging the authors to open-source their numerical calculation programs. Finally, we demonstrate the use of OPUCEM in two detailed case studies related to the fourth Standard Model family. The first is a generic fourth family study to find relations between the parameters compatible with the EW precision data and the second is the particular study of the flavor democracy predictions for both Dirac and Majorana-type neutrinos. Program summary Program title: OPUCEM (library) Catalogue identifier: AEIW_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEIW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 175 457 No. of bytes in distributed program, including test data, etc.: 1 061 012 Distribution format: tar.gz Programming language: C/C++ Computer: PCs and Workstations Operating system: Any Unix based system such as Linux and MacOSX, partial testing with Cygwin under Windows RAM: GUI takes about 25 MB, the individual library calls are negligible Classification: 11.1, 11.6 External routines: ROOT library set (optional), complex number constructs from either the C99 standard or from the C++ Technical Report 1 (ISO/IEC TR 19768) Nature of problem: The calculation of Electroweak Precision variables for each point of the parameter space of a given beyond the Standard Model theory is tedious and error prone. The available formulas in the literature sometimes contain typos and most of the time they are valid only under some specific conditions, not suitable for quick comparison across different studies nor direct implementation on a computer. Solution method: One loop exact calculation of the oblique parameters are collected into a freely available C/C++ library for a number of models. One-loop exact calculation of the contributions of a number of models to the oblique parameters are collected in a freely available C/C++ library. The public availability of the implementations and the internal error checking mechanism aim the correctness of the results. Additionally, the Graphical User Interface and auxiliary tools provide the means for rapid result comparison or update when new data becomes available. Unusual features: The library computes the oblique parameters S, T and U both with exact one-loop calculations and with well-defined approximations for a number of models to establish a certain level of confidence. The comparisons between exact and approximate computations, and amongst formulas from different papers provide an error checking machinery which improves the end user reliability. Running time: Fractions of a second for each function call Published by Elsevier B.V.