Interactions of the Higgs particle with nucleons, dark matter, and gravitons

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The Higgs particle plays a very special role in nature, because the universe is filled with a condensate of Higgs particles. Interactions of other known particles, e.g. electrons, with this condensate of Higgs particles gives mass to the other particles. Without mass, all particles would move at light speed and could not bind together to form structures like stars, planets, or our bodies. The Higgs particle therefore plays an important role in explaining the universe that we observe. The interactions of the Higgs particle with the known fundamental particles like electrons are well understood and verified through the discovery of the Higgs particle at the Large Hadron Collider (LHC). This success had an important Canadian contribution through Canada's partnership in the collaboration which operates the ATLAS detector at the LHC. However, besides its interactions with the known fundamental particles like electrons or quarks, the Higgs particle may also play another special role in nature as a messenger between the dark matter that makes up most of the mass in galaxies, and the "ordinary" matter that we can observe and manipulate in laboratories. Canada is also at the forefront of experimental searches for dark matter, either through collider based searches at the LHC, or through direct detection experiments at SNOLAB. I am particularly interested in the Higgs particle and its possible role in dark matter search experiments from a theoretical perspective. There are two kinds of interactions of the Higgs particle which are much less understood than its interactions with the known elementary particles, and those not well understood interactions play an important role for dark matter searches if the Higgs particle is the messenger to dark matter. Those two interactions are 1. the interaction of Higgs particles with atomic nuclei, and 2. the interactions of Higgs particles with dark matter particles. Both kinds of interactions of Higgs particles are important to relate dark matter theory to dark matter search experiments. My research program during the next five years will therefore focus on updating and extending theories of these interactions, in the hope to use the Higgs particle as a probe for dark matter both in collider experiments and in direct search experiments.