The heavy gluino in natural no-scale [formula omitted]-SU(5)

Thomas Ford,Tianjun Li,James A Maxin,Dimitri V Nanopoulos

doi:10.1016/j.physletb.2019.135038

Abstract

In light of recent 80–137 fb−1 results at the LHC Run 2 establishing a lower gluino mass limit of 2.25 TeV, we revisit the supersymmetric GUT model Flipped SU(5) with extra vector-like particles, known as F-SU(5), with vanishing No-Scale Supergravity boundary conditions at the string scale of about 2×1017 GeV, including the supersymmetry breaking Bμ parameter which is strictly enforced as Bμ=0. Given the proportional dependence of all model scales on a single parameter M1/2, No-Scale F-SU(5) was shown to possess no electroweak fine-tuning and thus persists as a natural one-parameter model. In this fresh analysis here, we demand consistency with the measured 125 GeV light Higgs boson mass, though we forgo an upper limit on the lightest neutralino relic density. The resulting phenomenology delivers a gluino mass of M(g˜)≲7.5 TeV and a lightest supersymmetric particle (LSP) of M(χ˜10)≲1.6 TeV. In order to dilute the relic density down to the WMAP and Planck measurements, we rely upon a single cosmological master coupling λ6.

Highlights

The ATLAS and CMS Collaborations recently released the 80–137 fb−1 results at the LHC Run 2 recorded from 2017–18, highlighted by no significant deviation beyond the expected Standard Model background [1]
The dearth of any positive signal of supersymmetry (SUSY) has elevated the lower bound on the gluino mass to 2.25 TeV with regards to the ATLAS and CMS g → tt + χ01 simplified model scenarios [2, 3]
The SUSY Grand Unification Theory (GUT) model Flipped SU (5) [9,10,11] with additional vector-like multiplets [12], better known as F SU (5) [14, 15], was shown to possess no electroweak finetuning within the construct of vanishing No-Scale Supergravity boundary conditions at the unification scale [16]

Summary

INTRODUCTION

The ATLAS and CMS Collaborations recently released the 80–137 fb−1 results at the LHC Run 2 recorded from 2017–18, highlighted by no significant deviation beyond the expected Standard Model background [1]. The advancement of gluino limits above 2 TeV further strains the SUSY model space, providing impetus for phenomenologists to build SUSY models supporting a heavy gluino, yet remain consistent with the measured light Higgs boson mass of Mh = 125.1 ± 0.14 GeV [4,5,6] and the WMAP 9-year [7] plus 2018 Planck [8] observed relic density on the dark matter content in our universe of ΩDM h2 ≃ 0.12, in addition to satisfying the world average top quark mass of Mt = 173.1 ± 0.9 GeV [6]. An analysis of No-Scale F -SU (5) in 2016 [21] showed a curious convergence of the observed central value of the light Higgs boson mass, world average top quark mass, and measured WMAP+Planck relic density upon the gluino mass range being probed at the LHC Run 2. May allow us to overproduce thermally produced LSPs that eventually may be diluted down to the right ΩDM h2, and open up the SUSY parameter space [23, 53]

ANALYTICAL PROCEDURE

Exc luded by Higgs Constraint Satisfies Higgs Constraint