Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

by Dr Hongwan Liu ( New York U. & Princeton U.)

Wednesday 17 Nov 2021, 10:00 → 12:00 Asia/Shanghai

Tsung-Dao Lee library/Fourth Floor-410 - 410# Meeting Room (Tsung-Dao Lee Library)

Abstract:

Dark matter particles may bind with nuclei if there exists an attractive force of sufficient strength. We show that a dark photon mediator of mass (10 -- 100) MeV with a small kinetic mixing with Standard Model electromagnetism generates keV-scale binding energies between dark matter and heavy elements, while forbidding the ability to bind with light elements.In underground direct detection experiments, the formation of such bound states liberates keV-scale energy in the form of electrons and photons, giving rise to mono-energetic electronic signals with a time-structure that may contain daily and seasonal modulations. We show that data from liquid-xenon detectors provides exquisite sensitivity to this scenario, constraining the galactic abundance of such dark particles to be a small subcomponent of the galactic dark matter density, with a mass of between 1 GeV and 100 TeV. However, an exponentially small fractional abundance of these dark particles is enough to explain the observed electron recoil excess at XENON1T.

Biography:

2019 –present Postdoctoral Associate, New York University and Princeton University

2014 – 2019 Doctor of Philosophy in Physics

 

Zoom information: https://cern.zoom.us/j/67203588271?pwd=WGhLUG1qaUpQNTkyUDNRWDB6ZUsvUT09

ID: 672 0358 8271 Password: 847080

20211116 TDLI:SJTU Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States.pdf