Dark matter clusters and time correlations in direct detection experiments
Shmuel Nussinov (School of Physics and Astronomy, Tel Aviv University, Chaim Levanon St., Tel Aviv, 69978, Israel); Yongchao Zhang (Department of Physics and McDonnell Center for the Space Sciences, Washington University, 1 Brookings Dr., St. Louis, MO, 63130, USA, Center for High Energy Physics, Peking University, No. 5 Yiheyuan Road, Beijing, 100871, China)
Assuming that dark matter (DM) efficiently clusters on various scales we analyse the possible impact on direct DM searches. For certain sizes and densities of DM clusters, mutual detector-cluster encounters may occur only once a year or every several years leading to the apparent failure of individual experiments searching for DM to discover it. If, however, encounters with Earth size and up to 104 times bigger clusters occur about once a year, then finding time correlations between events in different underground detectors can lead to DM discovery.
