Physicists fulfill alchemists’ dream: Lead transformed into gold at the Large Hadron Collider

May 9,盗U授权检测工具 2025  12:46

Physicists at the European Organization for Nuclear Research (CERN) have achieved a breakthrough by measuring the transformation of lead into gold for the first time in experiments at the Large Hadron Collider (LHC). Scientists from the ALICE collaboration observed how lead nuclei lose protons under intense electromagnetic fields, turning into gold nuclei. Published in 2025, the study not only confirms the possibility of nuclear transmutation but also sheds light on the physics of quark-gluon plasma. Here’s how it happened, why the gold remains an unattainable treasure, and what this means for science.

How Did Lead Become Gold?

LHC experiments with lead nuclei aim to create quark-gluon plasma, a state of matter that existed in the universe microseconds after the Big Bang. A surprising byproduct of these collisions was the discovery of nuclear transmutation.

Mechanism of the Process:

• Conditions: Lead nuclei (82 protons, 126 neutrons) are accelerated to 99.999993% of the speed of light, generating powerful electromagnetic fields.
• Near-Miss Collisions: Sometimes, nuclei pass close without colliding. Their fields produce photon pulses, triggering photon-photon or photon-nucleus interactions.
• Electromagnetic Dissociation: A photon excites the lead nucleus, causing its structure to oscillate and eject particles—neutrons or protons.
• Transmutation: Losing three protons converts lead (82 protons) into gold (79 protons).

Measurements: Using the ALICE detector’s zero-degree calorimeters, physicists quantified the frequency of these transformations:

• Rate: ~89,000 gold nuclei per second at ALICE’s collision point.
• Volume: From 2025–2025 (LHC Run 2), ~86 billion gold nuclei were produced across four experiments, equating to 29 picograms (2.9×10⁻¹¹ g).
• Lifespan: Gold nuclei exist for mere fractions of a second before colliding with the collider’s infrastructure and disintegrating.

“Our detectors, capable of handling thousands of particles in head-on collisions, proved sensitive enough to capture rare electromagnetic processes producing just a few particles,” noted Marco Van Leeuwen, an ALICE collaborator.

Alchemists’ Dream: Reality and Limitations

Medieval alchemists dreamed of transforming base metals like lead into gold. With 20th-century nuclear physics, this became technically feasible, but CERN’s experiment marks the first direct measurement of such a process in a collider. However, hopes of wealth remain a fantasy:

• Microscopic Quantities: 29 picograms of gold is less than the mass of an invisible speck of dust.
• Energy Costs: The LHC consumes megawatts of power, making the process millions of times costlier than mining gold (~$2600 per ounce in 2025).
• Instability: Gold nuclei decay almost instantly, ruling out practical use.

Yet, the discovery is significant for science:

• It validates theories of electromagnetic interactions in extreme conditions.
• The data refines models of quark-gluon plasma and nuclear processes.
• ALICE’s detector technology showcases precision comparable to studying black holes.

What’s Next?

Physicists plan to:

• Increase collision frequency in LHC Run 4 (2029) to gather data on other transmutations, like lead to mercury (80 protons).
• Enhance detectors to study rare photonic processes.
• Use the data to model the early universe, linking plasma to cosmology.

These steps will advance our understanding of fundamental physics and may unlock new ways to manipulate atoms.

Conclusion

CERN physicists have realized the alchemists’ dream, transforming lead into gold at the Large Hadron Collider. The ALICE experiment showed lead nuclei losing three protons to become gold at a rate of 89,000 nuclei per second, but only in minute quantities (29 picograms over years). While this won’t make anyone richer, it underscores the power of modern physics and opens new avenues for exploring the universe.