Astroparticle Colloquia

Three years results on annual modulation from ANAIS-112 experiment

by Prof. Maria Luisa Sarsa (Universidad de Zaragoza)




ANAIS (Annual modulation with NaI Scintillators) is a dark matter direct detection experiment consisting of 112.5 kg of NaI(Tl) detectors in operation at the Canfranc Underground Laboratory (LSC), in Spain, since August 2017. ANAIS’ goal is to confirm or refute in a model independent way the DAMA/LIBRA positive result: an annual modulation in the low-energy detection rate having all the features expected for the signal induced by dark matter particles in a standard galactic halo. This modulation is in strong tension with the negative results of other very sensitive experiments, but a model-independent comparison is still lacking. By using the same target material, NaI(Tl), such comparison is more direct and almost independent on dark matter particle and halo models. 

I will present the annual modulation analysis corresponding to three years of ANAIS data (for an effective exposure of 313.95 kgxy), applying a blind procedure which updates that developed for the 1.5 years analysis, and later applied to 2 years, while improves the background modelling in the fitting of the ROI rates. Our results support the absence of modulation in our data, and are incompatible with DAMA/LIBRA result at 3.3 (2.6) s in [1-6] ([2-6]) keV energy regions, for a sensitivity of 2.5 (2.7) s. Moreover, I will present some complementary analyses (phase-free annual modulation search and the exploration of the possible presence of a periodic signal at other frequencies) and consistency checks of our result, confirming our projected sensitivity for the scheduled 5 years of operation.