  Dwarf spheroidal galaxies are characterized by a large measured mass-to-light
ratio and are not expected to be the site of high-luminosity non-thermal
high-energy gamma-ray emissions. Therefore they are among the most promising
candidates for indirect searches of dark matter particle annihilation signals
in gamma rays. The Sagittarius dwarf spheroidal galaxy has been regularly
observed by the High Energy Stereoscopic System (H.E.S.S.) of Cherenkov
telescopes for more than 90 hours, searching for TeV gamma-ray emission from
annihilation of dark matter particles. In absence of a significant signal, new
constraints on the annihilation crosssection of the dark matter particles
applicable for Majorana Weakly Interacting Massive Particles (WIMPs) are
derived.
