Particle Astrophysics Group


December 2014

500 Citations

The LUX 2013 results paper is one of only two publications to garner more than 500 citations in other reviewed high-energy papers in 2014, on the popular community database INSPIRE. We think it is fair to say that it has fared better in the longer term than its co-highly cited paper for the year, the BICEP2 announcement. The LUX team is hoping that the imminent release of the re-analysis of the 2013 data will attract as much or more attention!

Start of new LUX dark matter campaign and re-analysis of 2013 data

LUX is searching for dark matter again. You may remember that on October 30, 2013, the LUX collaboration released the result of its first dark matter search run. Based on 85 days of accumulated live statistics, it established a new world record for sensitivity to WIMP spin-independent interactions over a wide range of possible particle masses. In particular, it probed possible WIMP models at very low masses (below 10 GeV) by a factor x20 beyond existing sensitivities.

This result was based on fairly conservative assumptions about the response of the detector at very low energy. In the last quarter of 2013, LUX performed extremely precise calibrations of the detector response to both electronic recoils and nuclear recoils at low energy, using two innovative techniques: injection of tritiated methane as a source of low-energy betas for electronic recoils, and an entirely new kinematic measurement of nuclear recoil energies from internal multiple scattering of neutrons provided by a D-D neutron generator. The analysis of this calibration data has allowed the collaboration to push its analysis threshold down, with preliminary performance presented at conferences in 2014. A re-analysis of the 2013 WIMP search data is currently being completed to take advantage of this new knowledge, and will be released publicly very soon.

At SURF, the first half of 2014 for LUX was also spent performing a few significant upgrades to the detector system for increased stability and performance. Data taking has resumed since the summer, including runs to finalize the next dark matter run parameters, taking ultra high-statistics calibrations for both electron recoil and nuclear recoil responses, and preliminary dark matter search data for quality assessment. The LUX experiment has begun its new dark matter search in earnest. It expects to collect over 300 live days of WIMP search data, and make further calibrations, extending the running into mid 2016. The collaboration expects to be able to release new search results from this data in late 2016.

(This story appeared in the SURF newsletter for December 2014)