New LHC Discovery Impacts Physicists' Hunt for Dark Matter

As scientists continue to search for dark matter in the universe, researchers have made some surprising new discoveries. CERN has announced that scientists on two separate Large Hadron Collider experiments have succeeded in measuring one of the rarest measurable processes in physics, the decay of B-subscripts-s mesons into two muons.

For the past 25 years, researchers have been searching for this evidence. The new findings match predictions made using the Standard Model of Particle Physics, which is huge for the future search for dark matter. The match, with only a 1 in 100,000 chance of being caused by a statistical error, essentially eliminates any possibility that B-sub-s meson decay is related to interaction with particles predicted by dark matter theories, as some physicists have suspected.

The Standard Model has been pieced together over the course of 40 years. A remarkably successful theory, it accurately predicts the behavior of fundamental particles. It's been put to the test again and again in various experiments. That said, there are some issues with the theory; it doesn't account for gravity and doesn't describe the so-called dark universe, which is why researchers continue to test it.

One of the experiments that captured the new data is called the Compact Muon Solenoid (CMS), an LHC component. The CMS finds tiny pieces of information in large groups of data when protons are smashed together at near-light speed in the world's largest collider. Useful data about subparticles produced by the collisions from background noise was then sorted out.

For every billion B-sub-mesons produced, only three or so are expected to decay into two muons, which are essentially heavier cousins of the electron. This theory has now been confirmed by the new data.

"It's extremely rare that it should decay this way," said Paul Padley, a co-investigator on the CMS experiment, in a news release. "But there has been the possibility it could decay through new particles predicted by dark matter theories, such as supersymmetry. If it were decaying through supersymmetric or other new particles, then the prediction of how often this decay should happen would be wrong. And we'd get a different answer."

In fact, there are several theories that predict that the result should be something different from the Standard Model. The fact that these experiments show otherwise means that scientists can apply the new findings to further hunts for particles.

Currently, the physicists are preparing for a next round of experiments to test other particles. That said, Padley is hoping to see something unexpected in the future.

"There's no such thing as a wrong result," said Padley in a news release. "All results tell us things. Unfortunately, the results keep telling us the Standard Model of Particle Physics works phenomenally well, and what we're seeing now is another stunning success of that model. But Mother Nature's also giving us this picture we know is full of dark matter and dark energy. She's waving dark matter and energy in front of us. We know it's there; we know it has to exist."

The findings from the two experiments can be found online here and here.