We know well the particles that make up our immediate surroundings. Collider experiments have also discovered some heavier particles such as the W and Z boson predicted by the Standard Model of particle physics. The Standard Model has held up incredibly well: the “i” was dotted by discovering the Higgs boson at the LHC at CERN. But what is most of the Universe made of is still a mystery. Indeed, our familiar baryonic matter makes up only 5% of it all. The rest is dark matter and dark energy.
We still do not know the answer to several fundamental questions: What is dark matter? Why is there more matter than antimatter? What gives neutrinos mass? Why are there three generations of particles? Why is the Higgs boson so light? To try to answer these questions, high energy theorists build models with new particles that do not belong to the Standard Model. Theorists then work out possible consequences of the models and make predictions for signals to be seen at the LHC accelerator, in dark matter detectors or in cosmic rays or gravitational waves.
Of course the model building goes hand-in-hand with astrophysics and cosmology: in the space and in the early Universe we have matter at extreme temperatures and densities where heavy particles – hitherto unknown to us – can be produced and play a role.
Our research interests in theoretical particle physics and high energy phenomenology are wide. We study various dark matter candidates from axion dark matter to WIMPs and primordial black holes. Since the dark sector could be as varied as the visible one, we take interests in dark photons and multi-scalar dark sectors. We consider dynamical symmetry breaking in dark matter models and study the ensuing cosmic phase transitions and gravitational wave signals from the early Universe.
We also develop models of flavour and neutrino mass, and study the connections to baryogenesis. We investigate fermion mass models with flavor symmetries, left-right symmetry and seesaw mechanisms in connection with scalar dark matter. Higher spin is studied in an effective field theory framework.
We work together with theorists in different universities and at CERN. We are also in close collaboration with the Estonian CMS experimental group.
