Speaker
David Nygren
(Lawrence Berkeley National Laboratory)
Description
The annual modulation signal observed by the DAMA-LIBRA Collaboration (D-L) is statistically strong and has been claimed by D-L as evidence for a dark matter signal. Lacking confirmation, an obligation endures to consider any plausible explanation based on conventional physics. The annual modulation may plausibly be explained as a consequence of energy deposited in the NaI(Tl) crystals by cosmic ray muons penetrating the detector. Delayed pulses in the approximate energy range of interest have been observed as a sequel to energy deposited by UV irradiation. I will argue that the same behavior may be reasonably expected to occur for energy deposited by any source of ionization or excitation. D-L can test this hypothesis by searching in current data for time correlations between muon events and pulses in the modulation energy range, or, for example, by renewed operation of the array at a sufficiently low temperature that freezes out the phenomenon.
Author
David Nygren
(Lawrence Berkeley National Laboratory)
