Research Interests
Our research group has a broad range of interests in high-energy physics, astroparticle physics and cosmology. Our focus is on both theoretical and phenomenological aspects of the new physics scenarios that could address some the outstanding puzzles of our universe, such as neutrino mass, matter-antimatter asymmetry and dark matter. Assuming that the scale of new physics might be within an experimentally accessible range (and there are good reasons for believing so), we are interested in analyzing testable models of new physics following the empirical clues and maximizing our chances of finding them within the foreseeable future at multiple fundamental frontiers, including the Energy, Intensity, Cosmic, Precision and Lifetime frontiers. Most of our research work is directly relevant to and maintains close connection with ongoing experiments (and experimentalists).
Energy Frontier
At the Energy frontier, currently spearheaded by the Large Hadron Collider (LHC), we may be able to directly search for the messengers of new physics, if kinematically allowed. We are particularly interested in the collider signals of various low-scale neutrino mass models and their complementarity with other low-energy searches. We are also trying to strengthen the case for the next-generation colliders by exploring their full physics potential beyond the reach of the LHC.
Selected Publications: 1808.00943, 1803.11167, 1711.08430, 1602.05947, 1502.06541
Intensity Frontier
At the Intensity frontier, we can search for rare processes involving very weak interactions, forbidden or suppressed in the SM, which could serve as a sensitive probe of new physics in a wide range of energy scales not accessible to the LHC. We are interested in studying the complementarity of the LHC searches for new physics messengers, such as sterile neutrinos, additional gauge and Higgs bosons, and other exotic particles with various low-energy rare processes, e.g., lepton flavor and/or universality violation, non-standard neutrino interactions, neutrinoless double beta decay, muon anomalous magnetic moment, electric dipole moment, neutron-antineutron oscillation and proton decay, for carving out the allowed new physics parameter space.
Selected Publications: 1712.02713, 1704.06659, 1703.00828, 1607.06832
Cosmic Frontier
At the Cosmic frontier, we make precision studies of key cosmological observables sensitive to new physics effects, such as the baryon-to-photon ratio, dark matter relic density, tensor-to-scalar ratio, etc, in order to address outstanding cosmological puzzles, such as the matter-antimatter asymmetry, dark matter and inflation. We are also paying close attention to the exciting recent developments in high-energy neutrino astronomy and gravitational wave astronomy, and in particular, how they can be made useful in probing new physics models.
Selected Publications: 1804.04919, 1609.03939, 1606.04517, 1605.09743, 1602.04203, 1404.1003
Lifetime Frontier
Long-lived particles are a common prediction of a wide range of theories that address unsolved fundamental mysteries like naturalness, dark matter, baryogenesis and neutrino masses, and represent a natural and generic possibility for physics beyond the SM. We are interested in testing some of these models at the future facilities, such as SHiP, DUNE and MATHUSLA.
Selected Publications: 1703.02471, 1612.09587
Precision Frontier
This genre of experiments are sensitive either to tiny deviations from the SM predictions (such as precision electroweak observables) or to rare phenomena that are highly suppressed or forbidden in the SM (such as neutrinoless double beta decay or lepton flavor violation). Our focus is in particular on the interplay of searches for charged lepton flavor violation and the neutrinoless double beta-decay of heavy nuclei with a next generation precision measurement of the parity-violating asymmetry in fixed-target experiments.
Selected Publications: 1806.08499