PHYSICS DISSERTATION DEFENSE: Saarik Kalia

Ph.D. Candidate:  Saarik Kalia

Research Advisor:  Peter Graham

Date:   April 18, 2022
Time: 2:00 PDT

Location: PAB 102/103

Zoom Link:  https://stanford.zoom.us/j/98750813136

Zoom Password: email nickswan@stanford for password

 

Title: Down-to-Earth Dark Matter: Novel Terrestrial Mechanisms for Dark Matter Detection

Abstract: There is overwhelming evidence for the existence of dark matter, a component of our universe which is more than five times as abundant as the visible matter we are familiar with.  Yet despite longstanding experimental efforts to search for non-gravitational interactions of dark matter, the detection of any such interactions has thus far eluded us.  There has therefore arisen an interest within the field in novel methods to detect dark matter.  In this thesis defense, I will outline two new methods which utilize Earth to detect two different types of dark matter.  The first searches for an oscillating magnetic field signal of ultralight bosonic dark matter at the surface of the Earth.  In analogy to existing cavity/shielded experiments searching for ultralight dark matter, the signal arises because the ground and ionosphere function as conducting cavity walls between which dark matter can source a magnetic field.  Based on this effect, we undertake an analysis of global geomagnetic field data from the SuperMAG collaboration in order to set bounds on dark photon and axionlike dark matter parameter spaces.  In the second half of my talk, I will discuss a proposal to use ancient rocks, dubbed paleo-detectors, as detectors for WIMP dark matter.  Over the past O(100) megayears, WIMPs may have induced nuclear recoils within these minerals that disrupted their crystalline structure, leaving long-lived tracks that can be read out today with precision microscopy techniques.  I will show that paleo-detectors can give unique sensitivity to dark matter substructure within the Milky Way.  This is because paleo-detectors are not only sensitive to the local dark matter density near the Earth today, but also to the dark matter density along Earth's entire galactic trajectory over the lifetime of a paleo-detector.