The Annual Modulation Signature for Dark Matter: DAMA/LIBRA-Phase1 Results and Perspectives

Table 2

Modulation amplitudes (1𝜎 error) obtained by fitting the time behaviours of the main running parameters including a possible annual modulation with phase and period as for DM particles. These running parameters, acquired with the production data are (i) the operating temperature of the detectors; (ii) the HP Nitrogen flux in the inner Cu box housing the detectors; (iii) the pressure of the HP Nitrogen atmosphere of the inner Cu box housing the detectors; (iv) the environmental Radon in the inner part of the barrack from which the detectors are, however, excluded; (v) the hardware rate above single photoelectron threshold. All the measured amplitudes are compatible with zero.

	DAMA/LIBRA-1	DAMA/LIBRA-2	DAMA/LIBRA-3	DAMA/LIBRA-4
Temperature (°C)	−(0.0001 ± 0.0061)	(0.0026 ± 0.0086)	(0.001 ± 0.015)	(0.0004 ± 0.0047)
Flux (L/h)	(0.13 ± 0.22)	(0.10 ± 0.25)	− (0.07 ± 0.18)	− (0.05 ± 0.24)
Pressure (10^−3 mbar)	(15 ± 30)	− (13 ± 25)	(22 ± 27)	(1.8 ± 7.4)
Radon (Bq/m^3)	− (0.029 ± 0.029)	− (0.030 ± 0.027)	(0.015 ± 0.029)	− (0.052 ± 0.039)
Hardware rate (10^−2 Hz)	− (0.20 ± 0.18)	(0.09 ± 0.17)	− (0.03 ± 0.20)	(0.15 ± 0.15)
	DAMA/LIBRA-5	DAMA/LIBRA-6	DAMA/LIBRA-7
Temperature (°C)	(0.0001 ± 0.0036)	(0.0007 ± 0.0059)	(0.0000 ± 0.0054)
Flux (L/h)	− (0.01 ± 0.21)	− (0.01 ± 0.15)	− (0.00 ± 0.14)
Pressure (10^−3 mbar)	− (0.8 ± 1.2)	(0.7 ± 1.3)	− (2.6 ± 5.5)
Radon (Bq/m^3)	(0.021 ± 0.037)	− (0.028 ± 0.036)	(0.012 ± 0.047)
Hardware rate (10^−2 Hz)	(0.03 ± 0.14)	(0.08 ± 0.11)	(0.06 ± 0.10)