Fermi 130 GeV gamma-ray excess and dark matter annihilation in sub-haloes and in the Galactic centre

TL;DR

This study confirms a 130GeV gamma-ray excess in Fermi-LAT data, suggesting it may originate from dark matter annihilation, with implications for particle physics and future collider searches.

Contribution

The paper provides the first detailed spectral analysis of the 130GeV excess, supporting dark matter annihilation as its origin and proposing new physics signals at the LHC.

Findings

Confirmed the 130GeV gamma-ray excess with 4.5 sigma significance.

Fitted dark matter annihilation spectra indicating line-like features.

Suggested a large annihilation cross-section compatible with a resonance at the LHC.

Abstract

We analyze publicly available Fermi-LAT high-energy gamma-ray data and confirm the existence of clear spectral feature peaked at E=130GeV. Scanning over the Galaxy we identify several disconnected regions where the observed excess originates from. Our best optimized fit is obtained for the central region of Galaxy with a clear peak at 130GeV with local statistical significance 4.5 sigma. The observed excess is not correlated with Fermi bubbles. We compute the photon spectra induced by dark matter annihilations into two and four standard model particles, the latter via two light intermediate states, and fit the spectra with data. Since our fits indicate sharper and higher signal peak than in the previous works, data favors dark matter direct two-body annihilation channels into photons or other channels giving only line-like spectra. If Einasto halo profile correctly predicts the central cusp of Galaxy, dark matter annihilation cross-section to two photons is of order ten percent of the standard thermal freeze-out cross-section. The large dark matter two-body annihilation cross-section to photons may signal a new resonance that should be searched for at the CERN LHC experiments.