Performance of ANAIS-112 experiment after the first year of data taking

Abstract

ANAIS is a direct detection dark matter experiment aiming at the study of the annual modulation expected in the interaction rate. It uses same target and technique as the DAMA/LIBRA experiment, which reported a highly significant positive modulation compatible with that expected for dark matter particles distributed in the galactic halo. However, other very sensitive experiments do not find any hint of particles with the required properties, although comparison is model dependent. In 2017, ANAIS-112 experiment was installed at the Canfranc Underground Laboratory (LSC), in Spain, and after the commissioning run for calibration and general assessment, ANAIS-112 started data taking in dark matter mode on August 3 rd , 2017. It consists of nine NaI(Tl) modules, amounting 112.5 kg of mass in total. Here we report on the experimental apparatus and detector performance after the first year of data taking. Total live time available amounts to 341.72 days, being the corresponding exposure 105.32 kg x yr. ANAIS-112 has achieved an analysis energy threshold of 1 keVee and an average background in the region of interest, from 1 to a Corresponding authors: mariam@unizar.es, mlsarsa@unizar.es b Deceased 6 keVee, of 3.6 counts/keVee/kg/day after correcting by the event selection efficiencies. In these conditions, ANAIS-112 will be able to test the DAMA/LIBRA result at three sigma level in five years of data taking.

Velocity substructure from Gaia and direct searches for dark matter

“…These include DM-Ice [167], KIMS [168], SABRE [169], Cosine [170,171] and ANAIS [172,173]. We do not provide a detailed fit to the DAMA/LIBRA data but instead focus our discussion on the general features introduced by the Dark Shards.…”

“…Although there is difficulty in explaining this signal with galactic DM while remaining consistent with other experiments, the signal does have many of the properties expected from galactic DM. ANAIS [172,173] and Cosine [170,171] have released first results and do not observe a statistically significant modulation, but they still require a few years of exposure to definitively test the DAMA/LIBRA result.…”

ANAIS-112 sensitivity in the search for dark matter annual modulation

“…The ANAIS experiment [1,2] is intended to search for dark matter annual modulation with ultrapure NaI(Tl) scintillators at the Canfranc Underground Laboratory (LSC) in Spain, in order to provide a model independent confirmation of the signal reported by the DAMA/LIBRA collaboration [3][4][5] using the same target and technique. Projects like DM-Ice [6], COSINE-100 [7,8], SABRE [9] and PICO-LON [10] also envisage the use of large masses of NaI(Tl) for dark matter searches.…”

“…Results obtained by a e-mail: icoarasa@unizar.es b Deceased other experiments with other target materials and techniques (like those from CDMS [11], CRESST [12], EDELWEISS [13], KIMS [14], LUX [15], PICO [16], XENON [17] or DarkSide [18,19] collaborations) have been ruling out for years the most plausible compatibility scenarios. Nevertheless, DAMA/LIBRA has accumulated up to now twenty annual cycles in the [2,6] keV ee energy region (keV ee for keV electron-equivalent) with 12.8σ statistical significance (phase and period fixed) [3][4][5]. Moreover, DAMA/LIBRA-phase2 has been able to accumulate six annual cycles in the [1,6] keV ee energy region with 9.5σ statistical significance because all the photomultipliers (PMTs) were replaced by a second generation PMTs Hamamatsu R6233MOD, with higher quantum efficiency and with lower background with respect to those used in phase1 [5].…”

“…The time-averaged differential rate is denoted by S 0 , whereas the modulation amplitude is given by S m [21]. The value of S m measured by DAMA/LIBRA is 0.0102 ± 0.0008 and 0.0105 ± 0.0011 cpd/kg/keV ee within [2,6] and [1,6] keV ee intervals, respectively (cpd stands for counts per day) [5].…”