Ancient alchemical aspirations are closer than ever to reality. In the ALICE (A Large Ion Collider Experiment), part of the Large Hadron Collider, the Large Hadron Collider (LHC), the transmutation of lead into gold has been experimentally measured through an unusual physical mechanism: interactions between nuclei that barely touch at speeds close to the speed of light.
CERN collider turns lead into gold – how is this possible?
Although the LHC is known for generating conditions that reproduce the early universe through head-on collisions, in this case the protagonists were a type of collision in which lead nuclei do not destroy each other, but rather their electromagnetic fields interact intensely, generating short-lived photon pulses that can modify the structure of the nucleus without direct contact.
When a lead nucleus (with 82 protons) loses three protons in these interactions, it temporarily becomes a gold nucleus (with 79). This happens in fractions of a second, and although gold atoms do not last, their existence has been quantified by the zero-degree calorimeters of the ALICE detector.
The role of the ALICE detector and the physics behind the phenomenon
The scientific team used the ZDC calorimetry system to count the photon-nucleus interactions, categorized by the number of protons emitted. The combinations make it possible to identify the ephemeral appearance of elements such as thallium, mercury and gold. During the second operational phase of the LHC, about 86 billion gold nuclei were generated. In the third phase, that number almost doubled.
The total mass, however, remains negligible: about 29 picograms. This figure is far from any economic application, but represents a fundamental advance in the understanding of nuclear processes under extreme conditions.
Impact for particle physics and accelerators.
Beyond the anecdotal, gold production at the LHC has serious implications for the design and optimization of future colliders. Electromagnetic dissociation models, necessary to predict losses in particle beams, are now validated and improved thanks to these results. In addition, the range of phenomena that can be explored with advanced detection technologies such as ALICE is extended.
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Source and photo: CERN
