Revisiting the Realistic Intersecting D6-Brane Model with positive and negative {\mu} Terms

TL;DR

This paper revisits a realistic intersecting D6-brane model in string theory, analyzing its parameter space under current experimental constraints, and identifies viable regions that satisfy collider, dark matter, and low-energy physics observations.

Contribution

It provides a comprehensive scan of the Pati-Salam D6-brane model's parameter space considering both signs of the  parameter, highlighting viable spectra and dark matter mechanisms.

Findings

Gravitino mass > 1.5 TeV in viable regions

Sparticle masses range from 0.5 to 18 TeV

Multiple dark matter coannihilation mechanisms identified

Abstract

In light of current constraints from supersymmetry (SUSY) searches within the LHC, as well as findings from direct dark matter detection experiments such as LUX-ZEPLIN (LZ), we revisit the three-family Pati-Salam model derived from intersecting D6-branes in Type IIA string theory compactified on the $T^6/(\mathbb{Z}_2 \times \mathbb{Z}_2)$ orientifold, known for its realistic low-energy phenomenology. Since the muon anomalous magnetic moment might be in accordance with the Standard Model prediction, we conduct a comprehensive scan over the model's parameter space for each sign of the Higgsino mass parameter, $\mu < 0$ and $\mu > 0$. We find that the gravitino mass is typically greater than 1.5 TeV in both scenarios while simultaneously satisfying the LHC SUSY bounds, B-physics observables, and the Higgs mass constraint. Within the experimentally viable region of the parameter space, the sparticle mass spectra fall within the following ranges: gluinos lie in the range 2-18 TeV; first- and second-generation squarks and sleptons span 3-16 TeV and 1-6 TeV, respectively. For third-generation sfermions, the lightest stop, which can satisfy the dark matter relic density via neutralino-stop coannihilation consistent with the \textit{Planck} 5$\sigma$ bounds, has a mass in the range 0.5-1.2 TeV. The lightest neutralino can be as heavy as 2.9 TeV. Additionally, the lightest stau can be as light as 200 GeV or as heavy as 5.2 TeV. We identify several viable mechanisms, including multiple coannihilation channels and resonance mechanisms, by which the observed dark matter relic abundance is successfully realized.