11–13 May 2026
University of Pittsburgh
US/Eastern timezone

Stress-Testing the 20 GeV Excess

12 May 2026, 16:45
15m
David Lawrence Hall 120, University of Pittsburgh

David Lawrence Hall 120, University of Pittsburgh

Speaker

Eve Schoen (UC Berkeley)

Description

A 20 GeV excess in the Fermi LAT gamma-ray sky has recently been reported by Totani and interpreted as a potential signal of dark matter annihilation. We independently reproduce this excess and systematically test its robustness. We evaluate the excess across more than 200 diffuse emission models, vary the region of interest, and examine spatial residuals. We additionally show the excess does not match observations of the Galactic center and perform a spectral-fit analysis to characterize the excess's energy dependence. While we confirm that the excess is present and statistically significant, we find that it does not behave fully consistently with a dark matter interpretation: its spatial properties deviate from those expected for annihilating dark matter and it is sensitive to diffuse model choices. Our results motivate caution in interpreting this feature as a dark matter signal.

Authors

Benjamin Safdi Eve Schoen (UC Berkeley) Joshua Foster (Massachusetts Institute of Technology) Nicholas Rodd

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