Supersymmetry Parameter Analysis: SPA Convention and Project

TL;DR

The paper proposes the Supersymmetry Parameter Analysis (SPA) Convention as a coherent framework to perform high-precision SUSY parameter analyses, defining pole masses for observables and ${\overline{\rm DR}}$ input parameters at ${\tilde{M}}=1$ TeV, with SLHA-based interoperability. It describes a comprehensive SPA program base that translates between schemes, computes spectra, decays, cross sections, low-energy observables, and CDM predictions, and integrates RG evolution and extended frameworks. An explicit benchmark, SPS1a', is introduced to test the tools and illustrate LHC/ILC capabilities for mass, coupling, and relic-density determinations. The overall goal is to enable coherent LHC+ILC analyses, accurate high-scale extrapolations, and reliable reconstruction of the underlying SUSY theory and its breaking mechanism.

Abstract

High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e+e- linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.

Figures (6)

• Figure 1: Running of the gaugino and scalar mass parameters as a function of the scale $Q$ in SPS1a$'$Porod:2003um. Only experimental errors are taken into account; theoretical errors are assumed to be reduced to the same size in the future.
• Figure 2: Total cross sections for squark and gluino pair production at the LHC Beenakker:1996chprospino for fixed gluino mass (top), squark mass (center), and gluino/squark mass ratio (bottom) [fixed parameters corresponding to SPS1a$'$ values]. Black circles indicate the SPS1a$'$ mass values. The Born cross sections (broken lines) are shown for some channels.
• Figure 3: Generic examples of total cross sections (Drell-Yan and Compton production) as a function of the average mass for production of sleptons, charginos and neutralinos at the LHC Beenakker:1996chprospino. The Born cross sections (broken line) are shown for comparison.
• Figure 4: Total cross section sections for chargino and neutralino pair production in $e^+e^-$ annihilation Oller:2005xg. The Born cross sections (broken lines) are shown for a few channels.
• Figure 5: Total cross sections for smuon and selectron pair production in $e^{\pm}e^-$ annihilation Freitas:2003yp. The Born cross section (broken lines) is shown for comparison.