For centuries, the transmutation of base metals into gold occupied the dreams of alchemists. While largely dismissed as pseudoscience, the pursuit wasn’t entirely unfounded in physical possibility – it simply required energies and conditions beyond historical reach. Now, a team led by Daniel Tapia Takaki, professor of physics at the University of Kansas, has demonstrated a fleeting, yet measurable, instance of this very transformation within the 17-mile Large Hadron Collider (LHC) beneath the French-Swiss border. The July 30, 2025, report isn’t a pathway to economic revolution, but a striking confirmation of nuclear physics and a crucial step toward optimizing the performance of current and future particle accelerators.
The LHC routinely accelerates heavy ions – in this case, lead – to velocities approaching the speed of light, colliding them to unlock the secrets of matter. However, this recent finding wasn’t born from direct collisions, but from what happens when these ions almost collide. These “ultraperipheral collisions,” as they’re known, occur when the nuclei pass close enough for their electromagnetic fields to interact intensely without physically touching. This interaction results in a shower of high-energy photons, and it’s these photons that can, momentarily, alter the composition of the lead nuclei. Specifically, the team found that the emission of three protons transforms lead-208 into gold-205, an existence lasting only about 10⁻²³ seconds. What’s particularly noteworthy isn’t that this happens, but how often – the analysis revealed a gold production rate with a cross section of 6.8 barns, remarkably close to the 7.67 barn rate of total inelastic lead-lead interactions at the same energy. This suggests that these near-miss transformations are surprisingly common within the LHC.
This discovery isn’t simply a modern echo of ancient alchemy. The significance lies in the clean environment these peripheral collisions create. Unlike the chaotic debris field produced by head-on collisions, these interactions are dominated by photons, allowing physicists to study nuclear structure and test fundamental theories of quantum electrodynamics (QED) with unprecedented clarity. Tapia Takaki’s team didn’t stumble upon this result; they meticulously re-tuned detector readouts, implemented “vetoes” to filter out unwanted signals, and refined a two-stage fitting process to isolate the telltale signs of proton loss from background noise. The team’s success in isolating these events, and quantifying their frequency, validates the theoretical predictions of models like RELDIS, while also highlighting areas where these models require refinement – particularly in understanding pre-equilibrium emission and nucleon coalescence in single proton channels.
Original reporting: earth.com.
It’s crucial to understand what the study didn’t find. Headlines proclaiming “scientists turn lead into gold” are, while technically accurate, deeply misleading. This isn’t a controllable process yielding usable quantities of gold. The transformation is fleeting, statistically rare on a per-ion basis, and requires the immense energy and specialized infrastructure of a facility like the LHC. The team also measured the rates for losing one and two protons, resulting in the creation of thallium and other isotopes, with rates of 40.4 and 16.8 barns respectively. These measurements, matching theoretical predictions within 25 percent, provide a comprehensive picture of the photonuclear reactions occurring within the collider.
However, limitations to consider exist. The analysis relies heavily on sophisticated modeling and correction techniques to account for detector limitations and potential “imposters” – events that mimic the signal of a photon-induced transformation. While Monte Carlo simulations suggest these imposters contribute less than one percent to the single proton sample, uncertainties remain. Furthermore, the current analysis is limited by the available data; the team is eagerly awaiting data from Run 3 of the LHC to extend their analysis to even more proton emissions, probing the creation of heavier nuclei like hafnium and tantalum.
The implications of this work extend far beyond fundamental physics. The loss of protons from lead ions, even in these peripheral collisions, can pose a significant operational challenge for particle accelerators. These stray ions can interact with sensitive components, potentially triggering shutdowns or safety systems. By precisely mapping these proton emission rates, Tapia Takaki’s team provides crucial data for engineers designing shielding and collimators for future accelerators, including the proposed 100-km Future Circular Collider. This data also informs simulations for the U.S. Electron Ion Collider (EIC), aiding in background rejection for precision measurements. The next steps involve refining photonuclear models to better match observed neutron-to-proton ratios and developing a dedicated trigger system that uses machine learning to capture these rare events in real-time. As we look ahead, the question isn’t whether we can create gold from lead, but whether we can harness this understanding to build more powerful, efficient, and safe particle accelerators – and what further secrets these machines will reveal about the fundamental building blocks of our universe.
