Disentangling Instrumental Features of the 130 GeV Fermi Line

TL;DR

This study investigates the instrumental characteristics of photons at 130 GeV in Fermi-LAT data to determine if the observed spectral peak is due to instrumental effects, using the sPlots algorithm to analyze various photon features.

Contribution

It applies the sPlots algorithm to separate signal and background photon features, providing insights into potential instrumental causes of the 130 GeV peak.

Findings

Identified suggestive instrumental features in the photon data

No statistically significant instrumental cause found due to limited data

Provides a framework for further instrumental analysis

Abstract

We study the instrumental features of photons from the peak observed at $E_\gamma=130$ GeV in the spectrum of Fermi-LAT data. We use the {\sc sPlots} algorithm to reconstruct -- seperately for the photons in the peak and for background photons -- the distributions of incident angles, the recorded time, features of the spacecraft position, the zenith angles, the conversion type and details of the energy and direction reconstruction. The presence of a striking feature or cluster in such a variable would suggest an instrumental cause for the peak. In the publically available data, we find several suggestive features which may inform further studies by instrumental experts, though the size of the signal sample is too small to draw statistically significant conclusions.