Global analysis of the pMSSM in light of the Fermi GeV excess: prospects for the LHC Run-II and astroparticle experiments

TL;DR

This paper performs a comprehensive global fit of the pMSSM-19 model, demonstrating its ability to explain the Fermi GeV gamma-ray excess and outlining prospects for detection at the LHC Run-II and future astroparticle experiments.

Contribution

It provides the first detailed global analysis of the pMSSM-19 in light of the Fermi GeV excess, identifying viable neutralino regions and predicting their detectability in upcoming experiments.

Findings

Two viable neutralino regions explaining the gamma-ray excess.

Neutralinos with masses ~80-100 GeV and ~180-200 GeV fit the data.

Upcoming LHC and Xenon1T experiments will probe these regions.

Abstract

We present a new global fit of the 19-dimensional phenomenological Minimal Supersymmetric Standard Model (pMSSM-19) that comply with all the latest experimental results from dark matter indirect, direct and accelerator dark matter searches. We show that the model provides a satisfactory explanation of the excess of gamma-rays from the Galactic centre observed by the Fermi~Large Area Telescope, assuming that it is produced by the annihilation of neutralinos in the Milky Way halo. We identify two regions that pass all the constraints: the first corresponds to neutralinos with a mass ~80-100 GeV annihilating into WW with a branching ratio of 95% ; the second to heavier neutralinos, with mass ~180-200 GeV annihilating into t tbar with a branching ratio of 87%. We show that neutralinos compatible with the Galactic centre GeV excess will soon be within the reach of LHC run-II -- notably through searches for charginos and neutralinos, squarks and light smuons -- and of Xenon1T, thanks to its unprecedented sensitivity to spin-dependent cross-section off neutrons.