Talks by Maxim Pospelov

Strange and exciting world of muonic atoms

Maxim Pospelov University of Minnesota

Recent landmark measurement of the muonic hydrogen Lamb shift generated more questions than answers, as it stands in a sharp disagreement with what was predicted based on known properties of muons and protons. It adds on top of the existing anomalies in the muon sector (discrepancy in g-2 and in radiative muon capture). I will critically review some suggestions for the new physics explanations of these anomalies, and describe their implications.

Sequestering Lorentz violation in the Lifshitz sector

Maxim Pospelov University of Minnesota
Horava's proposal to use Lifshitz propagators for gravitons above certain energy scales may provide a viable theory of quantum gravity without further need of UV completion. In my talk, I will address the question of whether the complete lack of Lorentz invariance above a certain energy scale is a big problem for any realistic construction. I will argue that it is not, provided that the onset of Lifshitz scaling for gravitons occurs at momentum scale much lower than the Planck mass. I will also discuss consequences of combining Lifshitz gravity and supersymmetric matter sector.

On the Relation Between the Invisible Higgs Decay and Dark Matter Scattering Cross Sections

Maxim Pospelov University of Minnesota
The simplest singlet Higgs-portal dark matter model predicts large/dominant Higgs ->2 DM decay widths in the region of parameter space with m_DM < m_h/2, and Higgs mass below 140 GeV. On the other hand, the direct detection experiments such as Xenon100 put stringent constraints on the scattering DM-nucleon scattering cross section and seemingly exclude large part of the parameter space where the invisible Higgs decay dominates over visible modes.