SUSY interpretation of the Egret GeV anomaly, Xenon-10 dark matter search limits and the LHC

TL;DR

This paper explores supersymmetric models to explain the Egret gamma-ray excess, examines constraints from WMAP and Xenon-10, and predicts detectable signals at the LHC and future dark matter experiments.

Contribution

It demonstrates that non-universal Higgs mass models can reconcile Egret, WMAP, and Xenon-10 constraints, and predicts observable collider and dark matter detection signals.

Findings

mSUGRA cannot satisfy all constraints simultaneously.

NUHM models can reconcile gamma-ray excess with dark matter detection limits.

LHC should observe gluino pair production with minimal data.

Abstract

The observation of the Egret experiment of an excess of diffuse gamma rays with energies above E_\gamma =1 GeV has previously been interpreted in the context of the minimal supergravity model (mSUGRA) as coming from neutralino annihilation into mainly b-quarks in the galactic halo, with neutralino mass in the vicinity of 50-70 GeV. We observe that in order to obtain the correct relic abundance of neutralinos in accord with WMAP measurements, the corresponding neutralino-proton direct detection (DD) rates should be in excess of recent limits from the Xenon-10 collaboration. While it does not appear possible to satisfy the Egret, WMAP and Xenon-10 constraints simultaneously within the mSUGRA model, we find that it is easily possible in models with non-universal Higgs soft masses (NUHM). In either case, gluino pair production from m(gluino)\sim 400-500 GeV should occur at large rates at the CERN LHC, and a gluino pair production signal should be visible with just 0.1 fb^{-1} of integrated luminosity. The NUHM interpretation predicts a rather light spectrum of heavy Higgs bosons with m_A\sim 140-200 GeV over the whole parameter space which would interpret Egret data. Spin-independent DD rates are predicted to be just above 10^{-8} pb, within range of the next round of direct dark matter detection experiments.