Protons are being accelerated to within a fraction of the speed of light somewhere beneath the Franco-Swiss border, in a 27-kilometer circular tunnel beneath small villages and farmland, and then they are being violently smashed together, briefly recreating conditions from the early universe. Since 2008, the Large Hadron Collider at CERN has been doing this, and for the majority of that time, the results, as impressive as they have been, have validated what physicists had already suspected.
The Standard Model, a theory developed in the early 1970s that describes 17 fundamental particles and three of the four fundamental forces of nature with remarkable precision, culminated in the discovery of the Higgs boson in 2012. For the most part, the Standard Model has been accurate. Because of this, the signals that have emerged from the data in recent years have been causing the kind of quiet, cautious excitement that physicists permit themselves when an unexplainable phenomenon keeps appearing.
Without much prodding, physicists will tell you that the Standard Model is not a complete theory. It has three noticeable gaps, but it accounts for everything composed of ordinary matter, including the electrons, quarks, gluons, and bosons that make up atoms and their interactions. Gravity is excluded because it is still incompatible with the quantum framework that underpins the rest of the Standard Model. Dark matter, the invisible material that astronomical observations indicate makes up about 26% of the universe and holds galaxies together in ways that visible matter alone cannot, is not explained by it. Furthermore, dark energy—the even more enigmatic force propelling the universe’s accelerating expansion—is not explained by it. It is estimated that dark energy and dark matter together make up about 95% of the universe. The remaining 5% are described by the Standard Model. There is a huge, well-known blind spot in that theory.
| Category | Details |
|---|---|
| Institution | CERN (European Organization for Nuclear Research) |
| Location | Geneva, Switzerland |
| Primary Instrument | Large Hadron Collider (LHC) |
| Detector Used | Compact Muon Solenoid (CMS) |
| Key Framework | Standard Model of Particle Physics (developed early 1970s) |
| Standard Model Particles | 17 known fundamental particles |
| What’s Missing from Standard Model | Dark matter, dark energy, gravity integration |
| Key Anomaly Type | Soft unclustered energy patterns; CP violation; lepton universality violations |
| Upcoming Experiment | SHiP (Search for Hidden Particles) — approved by CERN, starting ~2030 |
| Future Collider | Future Circular Collider (FCC) — estimated cost £12 billion, operational ~2040s |
| Higgs Boson Discovery | July 4, 2012 — ATLAS and CMS experiments at LHC |
| Key Researcher | Prof. Andrey Golutvin, Imperial College London (SHiP project) |
| Reference Website | CERN Official Site |
Since the confirmation of the Higgs, the main project at CERN has been the search for what lies beyond the Standard Model. The most recent noteworthy findings came from the CMS detector, which examined data gathered between 2016 and 2018 in search of what scientists refer to as “soft unclustered energy patterns”—subtle, low-energy signals that spread in all directions with an evenness that Standard Model physics doesn’t easily produce rather than forming into the neat particle jets typical of Standard Model processes.
The Hidden Valley, a hypothetical parallel sector of particles that interact with one another but hardly interact with the matter we can directly observe, is part of the theoretical framework that predicts these patterns. The two worlds would be connected by a so-called mediator particle, which would momentarily appear during high-energy collisions before decaying into Hidden Valley particles that eventually produce signatures that can be detected by devices like CMS.
The results of that specific search were negative; no soft unclustered energy patterns were discovered in the dataset, which provides physicists with valuable information even in the absence of a detection. The theoretical landscape was narrowed by the first exclusion of specific mass ranges for dark photons and mediator particles. “It’s a negative result, which is less exciting but an important part of a thorough search for new kinds of physics,” stated Daniel Whiteson, a UC Irvine physics professor who was not involved in the study. Physics eliminates incorrect answers through negative results, and eliminating incorrect answers has its own value.
Other anomalies, however, have proven more difficult to ignore. Lepton universality violations are instances where different types of leptons (such as electrons, muons, and tau particles) appear to be treated differently by fundamental forces when the Standard Model predicts they should behave identically. Over the years, CMS and its sister detector ATLAS have recorded hints of these violations. Leptons of different flavors should be interchangeable when it comes to force interactions, differing only in mass, according to a fundamental principle of the theory. It doesn’t fit when the data indicates otherwise. Upon closer examination, some of those signals have diminished. Some have persevered. Separately, scientists have discovered evidence of novel types of CP violation, such as asymmetries between matter and antimatter behavior, which are difficult for current theory to adequately explain. Experienced physicists tend to take the accumulation of minor discrepancies seriously, even though it’s still unclear if any one anomaly qualifies as a confirmed discovery.
A new experiment created especially to push into this area has now been approved by CERN. Particle detection will be approached in a fundamentally different way by the Search for Hidden Particles, or SHiP. SHiP will fire particles into a dense fixed target, smashing all of them simultaneously into smaller components, as opposed to the LHC’s method of colliding proton beams against one another. In order to detect these far-off decays, SHiP’s detectors are placed much farther away than traditional instruments. Ghost particles, if they exist, can travel tens or even hundreds of meters from a collision before disintegrating and revealing themselves.
The project’s leader, Prof. Andrey Golutvin of Imperial College London, called it “a new era in the search for hidden particles.” Around 2030, SHiP is expected to start up. It will cost about £100 million, a small portion of the £3.75 billion LHC and significantly less than the Future Circular Collider, a machine three times the circumference of the LHC that is currently estimated to cost £12 billion and won’t be fully operational until 2070.
Physics at this scale operates on timelines that are difficult for the average person to ignore. The 1964 theory of the Higgs boson was verified in 2012. It might take decades longer to find or completely rule out the particles that CERN is currently searching for. The slow and unglamorous process of getting closer to something is what physicists are doing in the interim: cataloging anomalies, excluding mass ranges, and testing edge cases in the data. It’s still genuinely unclear if what they’re getting close to is actually a new particle, a new force, or a mathematical artifact in the dataset. For fifty years, the Standard Model has been correct about nearly everything. However, there is still 95% of the universe that needs to be explained, and something is out there in the shadows.
