Resurrecting No-Scale Supergravity Phenomenology

TL;DR

This paper explores the viability of no-scale supergravity models within minimal supersymmetric SU(5) GUT, identifying parameter regions consistent with phenomenological constraints and discussing implications for sparticle detection at the LHC.

Contribution

It demonstrates the conditions under which no-scale supergravity can be consistent with phenomenological constraints in a GUT context, mapping the viable parameter space.

Findings

No-scale supergravity survives in a specific parameter space region.

Viable models require M_in  5 imes 10^{16} GeV and m_{1/2}  200 GeV.

Potential for detecting sparticles at the LHC in these models.

Abstract

In the context of phenomenological models in which the soft supersymmetry-breaking parameters of the MSSM become universal at some unification scale, M_{in}, above the GUT scale, \mgut, it is possible that all the scalar mass parameters m_0, the trilinear couplings A_0 and the bilinear Higgs coupling B_0 vanish simultaneously, as in no-scale supergravity. Using these no-scale inputs in a renormalization-group analysis of the minimal supersymmetric SU(5) GUT model, we pay careful attention to the matching of parameters at the GUT scale. We delineate the region of M_{in}, m_{1/2} and \tan \beta where the resurrection of no-scale supergravity is possible, taking due account of the relevant phenomenological constraints such as electroweak symmetry breaking, m_h, b \to s \gamma, the neutralino cold dark matter density \ohsq and g_\mu - 2. No-scale supergravity survives in an L-shaped strip of parameter space, with one side having with one side having m_{1/2} \gappeq 200 {\rm GeV}, the second (orthogonal) side having M_{in} \gappeq 5 \times 10^{16} GeV. Depending on the relative signs and magnitudes of the GUT superpotential couplings, these may be connected to form a triangle whose third side is a hypotenuse at larger M_{in}, m_{1/2} and \tan \beta, whose presence and location depend on the GUT superpotential parameters. We compare the prospects for detecting sparticles at the LHC in no-scale supergravity with those in the CMSSM and the NUHM.