Dark Matter (WIMPs) and its direct detection.

by Dr Jun-hui Liao (Brown University)

Thursday 23 May 2019, 11:00 → 12:00 Asia/Shanghai

B105 (CHEP)

I will be talking about Dark Matter (WIMPs) and its direct detection. Dark Matter (DM) is one of the most critical questions to be understood and answered in fundamental physics. Among other DM candidates, Weakly Interactive Massive Particles (WIMPs) is the most discussed one. WIMPs direct detection is research of multi-disciplines which wraps astrophysics, particle physics, and nuclear physics together and able to explore the untouching region of the interaction between WIMPs and nucleons in a way other methods like indirect detection and the searches on colliders cannot reach. I will firstly review the search of DM (WIMPs): the evidence of its existence from astrophysics and cosmology, the strategy of WIMPs detection, the current status of various experiments of WIMPs direct detection. Secondly, I will address two WIMPs direct experiments in details: DArk Matter In CCDs (DAMIC) and LUX-ZEPLIN (LZ) which hunt for low-mass (~ 1 - 10 GeV/c^2) and high-mass (~ 10 - 1000 GeV/c^2) WIMPs, respectively. For DAMIC, I will be talking about the quenching factor calibration for a silicon detector and the understanding of the interaction between WIMPs and nucleons under the context of Effective Field Theory (EFT). LZ is the most Spin Independent (SI) sensitive WIMPs searching detector at the stage of construction and has been fully funded by the Department of Energy (DOE), USA. I will introduce the project a little bit, the assembly of PMTs arrays at Brown. In the end, I will be proposing a brand new and world-leading experiment for low-mass (~ 100 MeV/c^2 - 10 GeV/c^2) WIMPs hunting with instrumental-backgrounds free thanks to the application of the powerful Pulse Shape Discrimination (PSD): A Liquid HElium Single phase TPC (ALHEST). With ~ 1 kg* yr exposure, ALHEST phase-I would achieve the region of WIMPs-nucleon elastic scattering one order lower than current limits (Spring of 2019) for ~ 100 MeV/c^2 - 10 GeV/c^2 WIMPs. The ~ 100s kg* yr exposure ALHEST phase-II is capable of reaching the sensitivity of 10^-45 cm^2 for the same mass region, which would touch the solar neutrino floor. ALHET could also be scaled up to multi-tonnes, therefore, is capable of researching both on DM and B-8 solar neutrinos. Mar 2018 - present, Senior scientist at Brown; LUX / LZ. Feb 2017 - Feb 2018, postdoc, Brown; LUX/LZ. Apr 2014 - Dec 2015, Fermilab (visiting scholar); DAMIC. Jul 2013 - Sep 2016, Graduate at University of Zurich, Switzerland; DAMIC. Mar 2009 - Jan 2013, research assistant, UCLouvain, Belgium; CMS. Jun 2005 - Feb 2009, CAS, IHEP, China; CSNS. L3 manager, responds for PMTs assembly. Deputy organizer, IDM 2018 conference. Invited by Springer, writing a book: "insightful understandings and practical experiences on nuclear and particle physics detector". NIM(A) reviewer since 2013