A dark matter portal into string theory

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Two major puzzles of modern physics concern the nature of dark matter and the problem of divergent calculations in quantum field theory. The problem of divergences is most succinctly expressed through the lack of a theory of quantum gravity and calls for an ultraviolet regulator. However, an ultraviolet regulator should also explain large cancellations in quantum field theory. We can infer this from the success of the renormalization program in gauge theories. Regularization of higher -order terms through mass and charge renormalization involves removal of ultraviolet divergences through infinite subtractions from "bare parameters". However, finite renormalization should not lead to excessively large parameter shifts. A regulator should therefore also imply a mechanism for cancellations in loop amplitudes to explain absence of excessively large renormalization effects in the presence of a large regulator scale. We have a candidate theory for an ultraviolet regulator that implies an elegant mechanism for large cancellations, viz. superstring theory, where cancellations can be effected by superpartners. String theory therefore still provides a promising framework for physics beyond the Standard Model and for quantum gravity. On the other hand, we have recently pointed out that the antisymmetric tensor fields of string theory provide a way to induce electroweak dipole dark matter couplings. This provides for a unique connection between string theory and dark matter and opens up the possibility of another potential dark matter window into string theory besides supersymmetric WIMPs and moduli. The proposed research project will therefore advance our understanding of both dark matter and string theory through further exploration of this connection with a PhD student. On the phenomenological side, the student will generalize our previous work on electron recoil signals from electroweak dipole dark matter to dark multiplets and update the direct search constraints. On the fundamental theory side, the student will also study the supersymmetric formulation of the electroweak dipole dark matter models. This will help to improve our understanding of the emergence of couplings between the antisymmetric tensor fields of string theory and electroweak dipole moments. The cost associated with the project is therefore almost completely incurred from the expenses for the PhD student's stipend. However, it is also beneficial to provide more students with the opportunity of benefitting from this unique training program to learn both string theory and dark matter research techniques. Therefore the project also provides training opportunities for undergraduate research students.