CERN’s 2025 Experiments: Hunting for Physics Beyond the Standard Model
Explore CERN's 2025 experiments at the LHC, hunting for physics beyond the Standard Model, from Higgs studies to dark matter searches.
- 8 min read
Introduction: The Cosmic Puzzle Awaits
Imagine standing at the edge of a vast, uncharted ocean, with only a map that covers half the territory. That’s where particle physics stands today. The Standard Model of particle physics, our best map of the universe’s fundamental building blocks, explains a lot—quarks, electrons, the Higgs boson—but it leaves gaping holes. What is dark matter? Why does the universe’s expansion accelerate? Why is gravity so elusive? These are the questions driving CERN, the European Organization for Nuclear Research, to push the boundaries in 2025 with experiments that could rewrite our understanding of reality.
At CERN’s Large Hadron Collider (LHC) and beyond, scientists are hunting for physics beyond the Standard Model (BSM). It’s like searching for a hidden room in a house you thought you knew inside out. With 2025 marking the fourth year of LHC’s Run 3 and new experiments on the horizon, the stage is set for breakthroughs that could reveal new particles, forces, or even dimensions. Let’s dive into the heart of CERN’s 2025 experiments, exploring the tools, discoveries, and dreams fueling this cosmic quest.
The Standard Model: A Brilliant but Incomplete Blueprint
The Standard Model is the cornerstone of particle physics, a framework that describes how particles like quarks and leptons interact via fundamental forces (electromagnetic, weak, and strong). It’s been a triumph, predicting the Higgs boson’s discovery in 2012 by ATLAS and CMS experiments at CERN. Yet, it’s incomplete:
- Dark Matter and Dark Energy: These mysterious entities make up ~95% of the universe, but the Standard Model offers no explanation. Dark matter binds galaxies; dark energy drives cosmic expansion. Neither fits the model’s framework.
- Gravity’s Absence: The Standard Model doesn’t incorporate gravity, the force shaping the cosmos at large scales.
- Matter-Antimatter Asymmetry: Why does matter dominate over antimatter in our universe? The Standard Model can’t fully account for this imbalance.
These gaps suggest new physics—particles, forces, or phenomena—lurking beyond our current understanding. CERN’s 2025 experiments are designed to find them, using the LHC’s unprecedented power and a suite of innovative detectors.
LHC Run 3: The 2025 Data Deluge
A New Season of Discovery
On May 5, 2025, CERN’s LHC kicked off its 2025 physics season, the fourth year of Run 3 (2022–2025). With proton collisions at 13.6 teraelectronvolts (TeV) and ambitious luminosity targets, the LHC is generating more data than ever. More collisions mean more chances to spot rare events that could hint at BSM physics. This year, the LHC also introduces a novel oxygen ion run in July, alongside lead ion collisions in October and November, to probe extreme states of matter like quark-gluon plasma.
ATLAS and CMS: The Heavy Hitters
The ATLAS and CMS experiments, the LHC’s largest, are general-purpose detectors designed to catch a wide range of physics phenomena. In 2025, they’re pushing the envelope:
- Higgs Boson Precision: Since its 2012 discovery, the Higgs boson has been a focal point. ATLAS’s 2024 Higgs2024 conference revealed searches for tri-Higgs production, a process 600,000 times rarer than single Higgs production. In 2025, ATLAS and CMS are refining Higgs measurements to spot deviations from Standard Model predictions, which could signal new physics.
- Top Quark Entanglement: In September 2024, ATLAS and CMS reported the first observation of quantum entanglement between top quarks at the LHC, the highest-energy entanglement ever observed. This opens new ways to test the Standard Model and probe BSM effects in 2025.
- Soft Unclustered Energy Patterns: CMS is searching for subtle energy signals that don’t form clear particle groups, known as “soft unclustered energy patterns.” These could indicate “Hidden Valley” models, where new particles (mediators) decay into dark-sector equivalents, potentially linked to dark matter.
LHCb: Probing Rare Decays
The LHCb experiment specializes in studying particles containing bottom quarks, like B mesons. In 2021, LHCb reported hints of a violation of lepton flavor universality, where B mesons decayed into electrons more often than muons, defying Standard Model predictions. While the statistical significance was 3.1 sigma (not yet a discovery), 2025’s Run 3 data could push this closer to the 5-sigma threshold, potentially hinting at a new force.
ALICE: Extreme Matter, New Insights
ALICE focuses on heavy-ion collisions to study quark-gluon plasma, a state of matter from the early universe. At the Quark Matter 2025 conference, ALICE presented new measurements of radial flow in this plasma, offering clues about strong interactions. These studies indirectly support BSM searches by refining our understanding of Standard Model processes.
Beyond the LHC: The Physics Beyond Colliders Program
While the LHC grabs headlines, CERN’s Physics Beyond Colliders (PBC) program explores BSM physics through high-intensity, high-precision experiments. Launched in 2016, PBC leverages CERN’s accelerator complex for complementary approaches. In 2025, several PBC experiments are making waves:
- NA62: Ultra-Rare Kaon Decays: In September 2024, NA62 confirmed the ultra-rare decay of a positively charged kaon into a pion and a neutrino-antineutrino pair (K+→π+νν), with a probability of less than one in 10 billion. This decay is highly sensitive to BSM effects, and NA62’s 2025 data collection aims to test for deviations that could indicate new physics.
- FASER: Neutrino Breakthroughs: In 2023, FASER made history by detecting collider-produced neutrinos at the LHC, a first. In 2025, FASER continues searching for dark photons and other light, weakly interacting particles, probing energy ranges up to several teraelectronvolts.
- SHiP: Hunting Hidden Particles: The Search for Hidden Particles (SHiP) experiment, proposed for CERN’s North Area, aims to detect “ghost particles” with weak interactions. By placing detectors far from collision points, SHiP could uncover hidden particles linked to dark matter, with plans advancing for post-2026 operations.
The Future Circular Collider: A Glimpse into Tomorrow
A Next-Generation Dream
The LHC’s days are numbered—by the early 2040s, it will reach its limits. CERN’s answer? The Future Circular Collider (FCC), a proposed 90.7-km tunnel that could host two machines:
- FCC-ee: An electron-positron collider for precision measurements, starting in the late 2040s, focusing on the Higgs and electroweak physics.
- FCC-hh: A hadron collider with energies up to 100 TeV, far surpassing the LHC, to probe new physics at unprecedented scales.
The FCC Feasibility Study, completed in March 2025, confirmed the project’s technical and financial viability. With an estimated €4 billion economic impact and 800,000 person-years of employment, the FCC is a bold bet on the future. However, funding remains a hurdle, and the CERN Council’s decision by late 2025 will shape its fate.
Why It Matters
The FCC’s higher energies and luminosity could detect light particles that interact weakly with Standard Model particles, like those proposed in Hidden Valley models. It’s like upgrading from a flashlight to a spotlight in the search for cosmic truths.
Challenges and Controversies
The Funding Dilemma
The FCC’s price tag is steep, and critics argue that funds could be better spent on other scientific priorities. With European taxpayers footing much of CERN’s bill, convincing the public of the FCC’s value is crucial. As Nature noted in March 2025, “waiting too long could mean a gap between the LHC’s closure and the FCC’s opening, risking the loss of expertise.”
The Elusive Breakthrough
Despite the LHC’s success, no clear BSM signals have emerged since the Higgs discovery. Some physicists, like Sneha Malde of LHCb, remain optimistic: “I have a strong feeling we will find something.” Others, like Jamie Boyd, LHC program coordinator, acknowledge the challenge: “We’ve looked in the easy places. Now we need to look harder.”
The Human Element: Stories from the Frontier
Behind the machines are thousands of scientists, engineers, and students. Take Nadjieh Jafari, a CMS physicist studying the top quark. She compares experimentalists to ancient explorers, chasing discoveries that could take decades to unfold. Or consider the ALICE PhD students honored in July 2025, whose thesis work on antimatter qubits could pave the way for testing fundamental symmetries.
These stories remind us that CERN’s quest isn’t just about particles—it’s about human curiosity, collaboration across 70+ countries, and the drive to answer life’s biggest questions.
What’s Next for 2025?
As Run 3 wraps up, 2025 is a pivotal year. Key experiments to watch include:
- ATLAS and CMS: New searches for supersymmetry, extra dimensions, and dark matter mediators.
- LHCb: Confirming or refuting the lepton flavor universality violation.
- NA62 and FASER: Pushing the boundaries of rare decays and neutrino physics.
- FCC Decision: The CERN Council’s strategy update by year-end will set the course for particle physics.
Conclusion: A Universe of Possibilities
CERN’s 2025 experiments are like a cosmic detective story, with the LHC and PBC as the sleuths hunting for clues beyond the Standard Model. Each collision, each rare decay, is a breadcrumb leading toward a deeper truth. Will we find dark matter? A new force? A hidden dimension? The answers may lie in the data pouring in this year.
As physicist Siegfried Fortsch put it, “Experimentalists are like the sailors who accompanied Christopher Columbus.” The journey is long, the destination uncertain, but the discoveries could change everything. Stay tuned—2025 might just be the year the universe reveals its next secret.
Useful Resources:
- CERN Official Website for experiment updates
- ATLAS Experiment for the latest physics results
- CERN Courier for in-depth articles on particle physics
Sources:,,,,,,,,,,,,,,