Researchers have created experimental results that establish detailed limits for the effective size of dark matter particles, using the XENON1T dark matter detector.

This sensitive XENON1T detector was able to limit this size parameter to 4.1X10-47 square centimeters, which is 1-trillionth of 1-trillionth of a centimeter squared.

Two background events, such as radon or gamma rays contamination, were predicted to occur in the detector, however, the contamination did not occur. Therefore, this suggests that dark matter particles are smaller than had been expected.

Ethan Brown, a member of the XENON Collaboration and physicist at Rensselaer Polytechnic Institute in New York, recently explained these finding to Space.com

“This is because they cannot differentiate between dark matter signals and background signals” Brown stated. “If we had seen a dark matter signal, we could have measured its size, but because we couldn’t see it, we can only say it has to be smaller than ‘this amount’,” Brown expressed.

He gave the example that, if there were two signals detected, they would be attributed to the two background events predicted. Since there were no events detected, background or dark matter, the dark matter “particles” must be smaller than anticipated.

These experimental results were presented May 28 at a seminar at the Gran Sasso Underground Laboratory (LNGS) in Italy. The detector uses liquid xenon and, whenever a dark matter particle collides with a xenon nucleus, if scientists’ models are correct, the collision should produce a small light flash — a rare opportunity to “observe” dark matter.

Theorizing that dark matter is five times as abundant as regular matter, researchers understand a minimum about the secretive substance. However, many scientists suspect dark matter is made of bodies called “weakly interacting massive particles” or “WIMPs” — particles that have a minimal reaction when encountering ordinary matter (like the faint light that flashes when WIMPs pass through a dense collection of xenon).

While the existence of WIMPs is not yet confirmed, it is a leading description of the elusive, invisible material.

“We now have the tightest limit for what is known as ‘the WIMP-nucleon cross section,’ which is a measure of the effective size of dark matter, or how strongly it interacts with normal matter,” Brown said in a statement. “With these results, we have now tested many new theoretical models of dark matter and placed the strongest constraints on these models to date.” [Dark Matter and Dark Energy Explained (Infographic)]

These experimental results are the culmination of 279 days of data, Elena Aprile, a project leader who is also from Rensselaer, added in the statement.