The Large Hadron Collider (LHC) is the most complex device ever built by humanity, and it’s allowed us to explore previously unknowable realms of physics. However, there are still some missing pieces to the puzzle. Scientists hope that a comparatively modest new instrument near the LHC could spot those missing pieces — missing particles, actually. The Massive Timing Hodoscope for Ultra Stable Neutral Particles is still just in the planning stages, but it could eventually spot stray particles escaping from the LHC.
The LHC began operating in 2008, with one of its primary goals to identify the Higgs Boson. This elementary particle, first hypothesized by Peter Higgs in 1964, is a vital piece of the so-called “standard model” of physics. The Higgs has to do with why other particles have mass. Data from the LHC has proven the Higgs Boson exists, but there’s still a problem with the Higgs: it’s not as massive as quantum mechanics predicts. So, physicists need to account for that missing mass. That’s where the new project could close the gap.
The Massive Timing Hodoscope for Ultra Stable Neutral Particles (which goes by the inaccurate but much simpler nickname MATHUSLA) will look for particles the LHC misses because they’re too stable. The LHC’s detectors, like the ATLAS instrument seen above, scan for the decay of exotic particles when protons smash together in the collider. These are usually mind-bogglingly short-lived, but researchers are beginning to suspect some of them might be more stable than expected. That’s why MATHUSLA is looking for “ultra-stable” particles. It’s right in the name.
MATHUSLA would essentially be a warehouse full of particle detectors stacked 20 meters tall at ground level above the LHC. Particles that streak away from the LHC without showing up in the data could appear in MATHUSLA’s detectors a split second later. A thick granite floor would be necessary to filter out the shower of less interesting particles, but anything left would be worth looking at more closely.
Scientists have good reason to suspect there are missing particles for MATHUSLA to see. Throughout history, the corrections introduced in physics to account for similar holes have turned out to be forces and particles we just didn’t know about at the time. Building MATHUSLA wouldn’t even be that expensive compared with the $10 billion Large Hadron Collider. MATHUSLA’s designers hope CERN, which operates the LHC, will step in and cover the $50 million cost to add MATHUSLA project.