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Dark matter (DM) in the GeV mass range which scatters off ordinary baryonic matter with a relatively large cross section is poorly constrained by existing experiments and observations. However, for a sufficiently large cross section, GeV DM particles can be captured and thermalized within Earth, resulting in the accumulation of a DM atmosphere whose number density can be as large as 10^14 cm^−3 at Earth’s surface. This DM atmosphere can be constrained by measuring the evaporation rate of liquid nitrogen in a storage dewar within which various materials are immersed. Neufeld and Brach-Neufeld performed experiments and reported limits on the DM-nucleus cross section. Because Born approximation is in general invalid in much of the relevant cross section regime, it is non-trivial to interpret such experimental results as a model independent limit on DM-nucleon cross section. We derive the constraints from the Neufeld experiments on the parameter space for DM-baryon scattering, with the interaction modeled as a Yukawa potential sourced by the finite sized nucleus. Combining the dewar constraints with BBN, we exclude for the first time a cross section above 10^-26 cm^2 for DM mass ~ 0.8 to 5.5 GeV. One DM model that isconstrained is sexaquark(uuddss)DM with massmX∼2GeV; it remains viable.
Research interest: Dark Matter, High Energy Physics, Astroparticle physics, Cosmology
Education:
September 2015 — May 2022 (expected), New York University, New York, NY, USA
Ph.D., in Physics, advisor: Glennys R. Farrar
September 2013 — May 2015, New York University, New York, NY, USA
M.Sc., in Physics
September 2008 — May 2012, Xiamen University, Xiamen, Fujian, China
B.Sc., in Physics
Honors and awards：
James Arthur Graduate Fellowship in New York University (2019)
First Grade Scholarship in Xiamen University (2008)