Event Details

In somewhat of a homage to Irving Langmuir’s lecture on pathological science, I will introduce the concept of Null Bias as I first came to experience it in the field of self-interacting dark matter. The current tightest upper limits on the self-interacting dark matter scattering cross-section are derived from null-results in the study of various merging galaxy cluster systems. However, as we and others have shown, many of the constraints derived from these null-results were stronger than the evidence supported. I will also suggest how null bias can be combatted based on the experience of the Merging Cluster Collaboration (MC2 ) which has recently completed its systematic three-year survey of 29 radio relic merging galaxy clusters, providing the largest and best calibrated sample of mergers to date. Finally, I will highlight the prevalence of null bias related to the concept of intermediate mass massive compact halo object (IM MACHO; ~10-105 Msolar) dark matter and outline our ongoing effort to address this null bias with a gravitational microlensing survey of IM MACHOs in the Milky Way.

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