The LUX-ZEPLIN (LZ) Dark Matter Search

Lead Research Organisation: Imperial College London
Department Name: Dept of Physics

Abstract

Direct dark matter experiments search for the extremely rare and very faint collisions expected to occur between the cold dark matter particles that are believed to permeate our galaxy and the nuclei of atoms in the active medium of a radiation detector. Weakly Interactive Massive Particles, or WIMPs, are hypothetical elementary particles weighing as little as a few protons or as much as several heavy nuclei; besides gravity, they would interact by the weak nuclear force, thereby providing a mechanics for their possible detection. The motivation to search for WIMP dark matter is strong, with theories that attempt to explain what lies beyond the Standard Model of Particle Physics providing very good candidates.

The LUX-ZEPLIN (LZ) experiment will deploy a 7-tonne liquid xenon WIMP detector at the 4850-foot level of the Sanford Underground Research Facility (SURF) after a 3-year construction phase. In this most quiet of environments, shielded from cosmic rays and local backgrounds, LZ will then operate for at least 3 years to hopefully find a handful of tell-tale signs of WIMP interactions. LZ will be so sensitive that it will be limited only by backgrounds from astrophysical neutrinos, which provide a fundamental limit to these searches. However, before neutrinos set in, this experiment has the potential to finally shed light on the nature of dark matter.

Planned Impact

This project will address the fundamental nature of the dark matter in the universe, of great importance to particle physics, astrophysics and cosmology. Our science output will directly impact these fields by constraining models of physics beyond the Standard Model and structure formation and evolution in the universe.

The technologies we are developing find wider and immediate benefit to other areas of physics within the STFC remit, notably long baseline neutrino oscillation experiments and neutrino-less double beta decay (0vBB) searches. Construction and operation of a multi-tonne noble gas time projection chamber impacts the UK and international neutrino physics communities seeking to develop detectors based on similar principles and technology. Challenges such as high voltage delivery, light collection, sensor readout, purification and electron transport, and long-term stability are all paralleled for proposed experiments such as LBNF, which could also be located at SURF, and with significant UK involvement. Similarly, LZ will develop and employ leading ultra-low background techniques to construct an instrument capable of detecting the rarest particle interactions. Experiments searching for rare 0vBB decay have similar requirements on stringent radio-purity. The UK 0vBB community and their international partners will benefit from our material screening instrument development and radiation detection techniques.

Our outputs developing low-background material screening technology will find further application in a diverse range of applications outside of physics. Mass-spectrometry instrumentation capable of detecting trace contaminants at parts-per-trillion levels in small samples provides unprecedented sensitivity for food safety, pharmaceutical, environmental, forensic and clinical research. Commercial service providers are limited in their capability due to regular exposure to high concentrations of impurities in their samples. We will validate our system against food safety and pharmaceutical standards from mid-2017. Demonstration of successful screening for toxicity in spiked samples, beginning with titanium dioxide nanoparticles, has the potential for improving safety standards and impacting UK health.

We will also investigate feasibility of measuring impact of uranium and thorium in silicon electronics chips from 2017. The alpha decays from U and Th progeny cause 'Single Event Effects' resulting in faults in integrated circuits; a problem that is increasingly significant as chips become smaller, and an area of active research. Coupled to our underground ultra-low background gamma spectroscopy capability, we can uniquely provide measures of the full U and Th chains, at sub-mBq/kg sensitivity, accounting for the complete alpha particle emission rates. Pre-screening Si and other construction materials with both mass spectrometry and gamma spectroscopy will allow manufacturers to increase reliability of their components and foster greater economic competitiveness of UK industry.

Our research provides training for students and staff in a wide range of specialist skills that are readily transferrable to commercial, financial and industrial sectors. Radiation detection technology and techniques are applicable to medical imaging and defence, particularly screening for special nuclear material. Data processing, analysis, statistical methods, programming, and Monte Carlo simulations are regularly employed in the banking and investment sectors. Construction of vacuum systems, gas recirculation and purification plants, photosensors and many other systems in LZ provide valuable engineering skills, as does project management training.

Finally, given the readily accessible nature of the topic of dark matter and deep underground operation, our research has always captured the public's imagination, providing significant outreach and engagement opportunity for dissemination of knowledge.

Publications

10 25 50
 
Description LZ Collaboration 
Organisation Brown University
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Case Western Reserve University
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Daresbury Laboratory
Country United Kingdom 
Sector Private 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Lawrence Berkeley National Laboratory
Country United States 
Sector Public 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Lawrence Livermore National Laboratory
Country United States 
Sector Public 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Rutherford Appleton Laboratory
Department Particle Physics Department
Country United Kingdom 
Sector Public 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation South Dakota School of Mines and Technology
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Stanford University
Department SLAC National Accelerator Laboratory
Country United States 
Sector Private 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Texas A&M University
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Alabama at Birmingham
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of California, Berkeley
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of California, Davis
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of California, Santa Barbara
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Coimbra
Department LIP Laboratory of Instrumentation and Experimental Particles Physics
Country Portugal 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Edinburgh
Country United Kingdom 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Maryland
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Oxford
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Rochester
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Sheffield
Department Department of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of South Dakota
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation University of Wisconsin-Madison
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description LZ Collaboration 
Organisation Yale University
Country United States 
Sector Academic/University 
PI Contribution Management, experimental design, R&D, construction-phase deliverables
Collaborator Contribution Management, experimental design, R&D, construction-phase deliverables
Impact Project in design/construction phase, no significant outputs yet
Start Year 2012
 
Description Cosmic Catch (Imperial Reporter) 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Featured in article entitled "Cosmic Catch" in Imperial Reported magazine (Aug. 2015 issue). The increased visibility of dark matter research from out work on the LUX and LZ experiments has been a contributing factor for College to make a new academic appointment in this general area.
Year(s) Of Engagement Activity 2015
URL http://www.imperial.ac.uk/media/imperial-college/staff/reporter/public/Reporter287web.pdf
 
Description Imperial HEP Masterclass 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Talk on Dark Matter Searches by A. Currie at the annual HEP Masterclass for O-level students
Year(s) Of Engagement Activity 2016
 
Description Imperial News feature (LZ approval) 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact "New dark matter detector gets green light" - Imperial News feature on the approval of the LZ experiment by the US funding agencies. This was disseminated to UK media organisations.
Year(s) Of Engagement Activity 2014
URL http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_18-8-2014-9-47-25
 
Description LZUK Website 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact LZUK website aimed at general public but also for information for undergraduate and postgraduate students, other researchers, and media.
Year(s) Of Engagement Activity 2016,2017,2018,2019
URL http://lz.ac.uk
 
Description Live interview, TALKRadio Sunday Show with Paul Ross 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Live interview on Dark Matter Searches and LZ, TALKRadio Sunday Show with Paul Ross
Year(s) Of Engagement Activity 2017
 
Description Talk to Year 7 and Year 8 Students at Dulwich Prep School (London) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk by A. Currie at Prep School followed by discussion.
Year(s) Of Engagement Activity 2017
 
Description Talk to Year-8 students at Dulwich Prep School (London) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Talk by A. Currie at Prep School followed by discussion.
Year(s) Of Engagement Activity 2016
 
Description The Blackett Colloquium 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Supporters
Results and Impact The first such event in this series for Physics Alumni at Imperial College, which aims to engage alumni in the research conducted in College.
Year(s) Of Engagement Activity 2015
URL http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/alumni/internationalambassadorevents/e...
 
Description ZEPLIN-III detector exhibit & Public Lecture at "Whitby & the Cosmos" exhibition, Whitby, UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact The ZEPLIN-III dark matter detector, which operated at the Boulby Underground Laboratory between 2007 and 2011, was adapted for public display at Imperial College London and donated to the Whitby Museum in late 2018 -- where it became the centrepiece of the topical exhibition "Whitby & the Cosmos". I gave a public lecture entitled "Searching for WIMPs under the Moors" on 15 Feb 2019 to open the event. The ZEPLIN-III instrument will be moved to the permanent collection of the Museum once the exhibition comes to an end in July 2019. Both the exhibition and the public lecture were widely publicised in the local media. The Museum received further support from the Royal Society for this event. The exhibition will receive many thousand of visitors over the coming months. We had the opportunity to donate the instrument to the Science Museum in London, but we chose the Whitby Museum instead to honour a town which hosted the ZEPLIN collaboration for two decades.
Year(s) Of Engagement Activity 2019
URL https://whitbymuseum.org.uk/2019/01/09/whitby-and-the-cosmos/