Last week was yet another exciting moment for those of us who are researching the nature of dark matter. The long-awaited XENON(100) results were released. XENON, is the biggest rival to my own experiment, the Cryogenic Dark Matter Search, or CDMS. In the world-wide race to discover dark matter, XENON and CDMS have been leading the pack over the past few years. These two experiments have been taking turns nudging ahead of each other, only to have the other pull ahead within about a year’s time. This time around, XENON has made a fairly big leap ahead. While the XENON collaboration did not report a discovery, their data does provide significant new constraints on the many theories that aim to explain dark matter. Their new result has lowered the possibility for dark matter interactions by a factor of ~4 over previous world limits.
I’m certain two of the big questions many now have for CDMS, are: What are our plans for the future and will we be taking the next jump that puts us in the lead? Though we’ve had a setback recently, I’m optimistic about CDMS. We are in the process of starting a new phase of the experiment named SuperCDMS. For SuperCDMS, we will implement a new detector design which will significantly increase our sensitivity to WIMPs. Last month, we were in the middle of testing these detectors when a fire broke out in the mine where the experiment resides. We are now waiting while the mine infrastructure is repaired. Once that is completed, we will begin our first physics run with the new detectors, which may be as soon as this summer. In the meantime, we are planning a much bigger version of the experiment at a much deeper underground site, SNOLAB in Canada. Both of these endeavors have planned sensitivities that exceed the current XENON limits.
In the meantime, of course, the XENON collaboration will be continuing to gather more data and working on their next-generation experiment. However, based on their reported results, it is clear that they cannot simply improve their sensitivity with more of the same data. To push their sensitivity further, they must reduce intrinsic radioactive contaminants in their detector. Though they claim to have started a new run with higher purity levels, it’s unclear how long they can sustain the current conditions of the detector.
So the worldwide race has tipped toward XENON for the time being, but meanwhile, the future of CDMS is bright. We don’t yet know what nature has to reveal or what the future will bring. This makes the world of dark matter research fascinating. No matter what happens, we all look forward to learning what the final outcome will be. For me, these are great reasons to push forward in the race to understand dark matter.
— Lauren Hsu