Severo Ochoa Seminar: Testing DAMA/LIBRA result with ANAIS-112 experiment at the Canfranc Underground Laboratory

by Susana Cebrián Guajardo (Universidad de Zaragoza)

Friday 10 May 2019, 12:00 → 13:00 Europe/Madrid

4-4-4426 - Seminari Física Teòrica (Campus Burjassot)

DAMA/LIBRA observation of an annual modulation in the detection rate compatible with that expected for dark matter particles in the Milky Way’s halo is for about two decades one of the most puzzling experimental results in the field. It has neither been confirmed nor ruled out in a model independent way, despite the impressive improvement in sensitivity in dark matter direct detection experiments based on new detector technologies combined with strong background suppression. ANAIS experiment, using 112.5 kg of sodium iodide as target, is taking data at the Canfranc Underground Laboratory in Spain since August 2017 aiming at testing the observation by the DAMA/LIBRA experiment using the same target and technique.  

The first model independent testing of this result has just been presented [1]: 1.5 years from ANAIS-112 experiment have been analyzed searching for modulation. Results are compatible with the absence of modulation and incompatible with DAMA/LIBRA signal at 90% C.L.; in particular, the best fits for the modulation hypothesis give amplitudes Sm=-0.0044±0.0058 cpd/kg/keV and -0.0015±0.0063 cpd/kg/keV for the [2-6] and [1-6] keV energy regions, respectively. These results are in agreement with our estimated sensitivity for the accumulated exposure, supporting our projected goal of reaching a 3σ sensitivity to the DAMA/LIBRA result in 3.5 more years of data-taking. Before unblinding the data, the whole analysis procedure was fixed [2], the background of the experiment thoroughly studied [3] and the expected sensitivity for the five-year operation evaluated [4].

In this seminar, after posing the DAMA/LIBRA conundrum, the ANAIS-112 experiment will be firstly described presenting the set-up, performance, analysis methods and background model developed. Then, the obtained results from the annual modulation analysis will be shown and their implications and the future prospects will be discussed.

[1] First results on dark matter annual modulation from ANAIS-112 experiment, J. Amaré et al, http://arxiv.org/abs/1903.03973  (submitted for publication in Phys. Rev. Lett.) 
[2] Performance of ANAIS-112 experiment after the first year of data taking, J. Amaré et al, Eur. Phys. J. C (2019) 79:228, http://arxiv.org/abs/1812.01472 
[3] Analysis of backgrounds for the ANAIS-112 dark matter experiment, J. Amaré et al, http://arxiv.org/abs/1812.01377  (review in progress for publication in Eur. Phys. J. C) 
[4] ANAIS-112 sensitivity in the search for dark matter annual modulation, I. Coarasa et al, Eur. Phys. J. C (2019) 79:223, http://arxiv.org/abs/1812.02000