School Colloquia Series - Dark Matter Variation of the Fundamental Constants and Violation of the Fundamental Symmetries
Speaker: Prof Victor Flambaum
Astrophysical observations indicate that 85% of the matter content in the Universe is due to dark matter, the identity and properties of which remain a mystery. Traditional searches for the scattering of dark matter particles off nuclei have not yet produced a strong positive result. The challenge with these traditional searches is that they look for effects that are fourth power in a very small interaction constant. We discuss effects of the first power in the interaction constants, which may give an enormous advantage.
The low mass boson dark matter particles produced after Big Bang form an oscillating classical field and/or topological defects. Interactions with these fields produce a cosmological evolution of the fundamental constants such as the strength of the fundamental forces (including electromagnetism), as well as the masses of the particles. Variations in these physical constants leave characteristic fingerprints on physical processes that take place from as early as a second after the birth of the Universe until the present day.
By studying the effects of dark matter on the primordial abundance of helium produced in the first few minutes of the Universe and on atomic systems in the laboratory, we have derived limits on the interactions of dark matter with photon, electron, quarks and Higgs boson, which improve on existing constraints by up to 15 orders of magnitude, as well as the first ever limits on the interactions of dark matter with the W and Z bosons. Further progress may be achieved with laser interferometry experiments (such LIGO which detected gravitational waves) and pulsar timing.
Other effects of dark matter include oscillating spin-precession and oscillating parity and time reversal violating effect.
Finally, we explore a possibility to explain the DAMA collaboration claim of dark matter detection by the dark matter scattering on electrons. We have shown that the electron relativistic effects increase the ionization differential cross section up to 3 orders of magnitude.