Direct and indirect searches for anomalous beta decay
Abstract
We present a treatment of time-varying nuclear transition rates intended to guide future experimental searches, focusing primarily on the concept of "self-induce decay.'' This investigation stems from a series of recent reports that suggest that the decay rates of several isotopes may have been influenced by solar activity (perhaps by solar neutrinos). A mechanism in which (anti)neutrinos can influence the decay process suggests that a sample of decaying nuclei emitting neutrinos could affect its own rate of decay. Past experiments have searched for this "self-induced decay" (SID) effect by measuring deviations from the expected decay rate for highly active samples of varying geometries. Here, we further develop a SID formalism which takes into account the activation process. In the course of the treatment, the observation is made that the SID behavior closely resembles the behavior of rate-related losses due to dead-time, and hence that standard dead-time corrections can result in the removal of possible SID-related behavior. Additionally, we discuss a long-running dark matter (DM) experiment which observes an annual signal predicted by standard DM models. Here, we consider the possibility that the annual signal seen by the DAMA collaboration, and interpreted by them as evidence for dark matter, may in fact be due to the radioactive contaminant 40K, which is known to be present in their detector. We also consider the possibility that part of the DAMA signal may arise from relic big-bang neutrinos.
Degree
Ph.D.
Advisors
Fischbach, Purdue University.
Subject Area
Astrophysics|Nuclear physics
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