Report of the Beyond the MSSM Subgroup for the Tevatron Run II SUSY/Higgs Workshop

Abstract

Abstract.There are many low-energy models of supersymmetry breaking parameters which are motivated by theoretical and experimental considerations. Some of these approaches have gained more proponents than others over time, and so have been studied in greater detail. In this contribution we discuss some of the lesser-known theories of low-energy supersymmetry, and outline their phenomenological consequences. In some cases, these theories have more gauge symmetry or particle content than the Minimal Supersymmetric Standard Model. In other cases, the parameters of the Lagrangian are unusual compared to commonly accepted norms (e.g., Wino LSP, heavy gluino LSP, light gluino, etc.). The phenomenology of supersymmetry varies greatly between the different models. Correspondingly, particular aspects of the detectors assume greater or lesser importance. Detection of supersymmetry and the determination of all parameters may well depend upon having the widest possible view of supersymmetry phenomenology. I INTRODUCTIONMost of the studies performed to assess the discovery reach for supersymmetry and most of the current limits on the masses of supersymmetric particles have been obtained assuming R-parity conservation, the minimal matter content of the Minimal Supersymmetric Model (MSSM), and universal boundary conditions at M U for the soft-SUSY-breaking parameters: m 0 for the scalar masses; M 0 for the SU(3),SU(2) and U(1) gaugino masses M 3,2,1 ; and A 0 for the tri-linear scalar field couplings. Additional parameters of the MSSM include: tan β, the ratio of Higgs field vacuum expectation values H u / H d ; µ, the coefficient of the bilinear H u H d superpotential term; and B, which specifies the strength of the corresponding H u H d scalar field mixing term. By requiring correct electroweak symmetry breaking after evolution down to the scale m Z , the magnitude of µ is fixed and only its sign remains undetermined.This boundary condition scenario is often referred to as the mSUGRA or CMSSM model. If unification of the τ and b Yukawa couplings at M U is required, then correct EWSB strongly constrains tan β as well. While the matter content and boundary conditions of the MSSM have the virtue of simplicity and can be reasonably motivated in the context of several types of gravity-mediated supersymmetry breaking, other possibilities should certainly be considered. For a model with MSSM matter content and R-parity conservation, the most general form of soft-SUSY-breaking allows for a total of 124 parameters (not counting certain additional parameters expected to be suppressed by 1/M U factors). This is to be compared to the 19 parameters of the Standard Model. The most general form of R-parity violation increases the parameter count to 315. Some of these parameters are associated with phases and CP violation. A summary appears in Table 1. A final parameter is the mass of the gravitino, G. If the scale of supersymmetry breaking is sufficiently low, m G can be small enough that it is the LSP. In particular, this is the expectati...