Anson Hook (UMD) “Relaxing the Higgs Mass” Abstract: We present a new approach to the Hierarchy problem utilizing self organized criticality. The Higgs mass is generically large, but when expanded around the minimum of the potential, the Higgs mass is small. This approach is analogous to models of the dilaton where the quartic is large at tree level, but is … Read More
Tobias Binder (IPMU) “Dark matter quantum mechanical effects at finite temperature” If WIMPs are realized around the TeV-mass region or above, even the heaviest electroweak force carriers could act as long-range forces, leading to a variety of quantum mechanical effects such as the existence of meta-stable DM bound states. The formation and subsequent decay of the latter further deplete the … Read More
Donal O’Connell (Edinburgh)“Quantum Amplitudes and Classical Gravity” ABSTRACT:Scattering amplitudes in quantum field theory have received a lot of attention in recent years. We have learned that amplitudes provide a surprising link, known as the double copy, between Einstein gravity and Yang-Mills theory. I will explain why the double copy persists at the classical level, and discuss the resulting two-way flow … Read More
Sterile neutrino is a very simple dark matter candidate. In the minimal incarnation, the original Dodelson-Widrow mechanism that explains its relic abundance is in strong tension with indirect detection constraints. I present the self interacting neutrino scenario, mediated by a Majoron-like scalar or vector boson, as a novel solution to the above tension. It opens up new & wide parameter … Read More
I will discuss the on-shell formulation of effective theories, focusing on extensions of the electroweak sector. I will describe a systematic construction of bases for general massive 4-point amplitudes, utilizing the relations between massive and massless spinor amplitudes via (un)bolding. We will also see how properties of Higgsed gauge theories emerge from on-shell massive amplitudes.
Particle Theory Seminar | Sebastian Baum (Stanford): Paleo-Detectors – Digging for Dark Matter and Neutrinos Paleo-Detectors are natural minerals which record damage tracks from nuclear recoils over geological timescales. Minerals commonly found on Earth are as old as a billion years. Modern microscopy techniques may allow to reconstruct these damage tracks with nanometer scale spatial resolution. Thus, paleo-detectors would constitute … Read More
If even a relatively small number of primordial black holes (PBH) were created in the early universe, they will constitute an increasingly large fraction of the total energy density as space expands. It is thus well-motivated to consider scenarios in which the early universe was dominated by short lived PBH (M < 10^9 grams, t 10^11 GeV) to avoid overproduction. … Read More
Noble-alkali comagnetometers offer the exciting possibility of detecting the anomalous magnetic fields sourced by ultralight axion-like particles. I will discuss an on-going reanalysis of data from a helium-potassium comagnetometer at Princeton, which is expected to yield world-leading sensitivity to axion-neutron couplings in the mass range from to eV. This analysis requires a careful treatment of the stochastic fluctuations of the … Read More
For the past few decades, our understanding of structure formation on sub-galactic scales has been thought to have several outstanding issues, including the “missing satellites problem.” In the advent of improved sensitivity to faint satellites with galaxy surveys, as well as purely gravitational probes of dark low-mass sub-halos, it appears that there is no missing satellites problem and the satellites … Read More
Abstract: The quantum chromodynamics axion is a well-motivated dark matter candidate that may also solve the strong CP problem related to the absence of the neutron electric dipole moment. Multiple experimental efforts are currently racing to try to discover this particle in the laboratory. In this talk I will show that astrophysical observations are also a promising path towards detecting … Read More