  We discuss the potential for using neutron stars to determine bounds on the
Higgs-Kretschmann coupling by looking at peculiar shifts in gamma-ray
spectroscopic features. In particular, we reanalyse multiple lines observed in
GRB781119 detected by two gamma-ray spectrometers, and derive an upper bound on
the Higgs-Kretschmann coupling that is much more constraining than the one
recently obtained from white dwarfs. This calls for targeted analyses of
spectra of gamma-ray bursts from more recent observatories, dedicated searches
for differential shifts on electron-positron and proton-antiproton annihilation
spectra in proximity of compact sources, and signals of electron and proton
cyclotron lines from the same neutron star.

Instrumentation and Methods for Astrophysics;High Energy Astrophysical Phenomena