Decay or annihilation products of superheavy dark matter ( SHDM ) could be responsible for the end of the Ultra-High Energy Cosmic Ray ( UHECR ) spectrum .
In this case , the south array of the Pierre Auger Observatory should observe in the future a significant anisotropy of UHECR arrival directions towards the galactic center .
Here we use the already existing data of the SUGAR array to test this possibility .
If decaying SHDM is distributed according a Navarro-Frenk-White ( NFW ) dark matter profile with core radius R _ { c } = 15 kpc and is responsible only for UHECRs above \sim 6 \times 10 ^ { 19 } eV , i.e .
the AGASA excess , then the arrival directions measured by the SUGAR array have a probability of \sim 10 \% to be consistent with this model .
By contrast , the model of annihilating SHDM is disfavoured at least at 99 % CL by the SUGAR data , if the smooth component of the DM dominates the signal .