Crossing the Intensity Frontier
In the hunt for new particles, physicists look at ever higher energy particle collisions, moving the energy frontier. Some particles however are elusive not due to their high energy, but because they rarely interact. This raises a new barrier: the intensity frontier.
Colossal particle accelerators like CERN’s Large Hadron Collider (LHC) are capable of inducing collisions between particles at incredible speeds. This adds enormous amounts of energy to the impact, which end up in newly created particles. When scientists look for the existence of new massive particles, they need sufficient energy to convert into mass and therefore aim to pass an “energy frontier”. For the discovery of the Higgs boson, the LHC succeeded in passing first the 8 TeV and later the 13 TeV frontier.
Leiden physicist Alexey Boyarsky looks for particles that might be lurking behind a different barrier—the “intensity frontier”. Scientists suspect that some particles are so difficult to create not due to their high mass, but because they interact so rarely. This would mean that billions of collisions are needed to produce a single “feebly interacting particle”. CERN’s Search for Hidden Particles (SHiP) experiment, for example, is pushing the intensity frontier forward by several orders of magnitude.
Together with physicists around the globe, Boyarsky has organized a workshop called New Physics at the Intensity Frontier at CERN in Geneva with over 100 participants from 21 countries. ‘The main outcome of the workshop is that the intensity frontier is under-explored,’ Boyarsky says. ‘There is a lot of possible new physics to be searched for there. It is possible that with the help of these experiments, we will find explanations for the main puzzle around physics beyond the standard model: dark matter, matter-antimatter asymmetry and neutrino masses.’