From lead atoms: tens of thousands of gold atoms created every second at the LHC

At the world's largest particle accelerator, the LHC, around 89,000 lead atoms are currently being converted into gold atoms every second. This is an old alchemist's dream come true, so to speak. This has been determined by a research group at the Large Hadron Collier. According to their analysis, a total of 86 billion gold atoms were created in this way between 2015 and 2018, and twice as many in the subsequent third run. However, because this is still only a few dozen picograms of the precious metal, it would still take trillions of times this amount to produce even one piece of jewelry, the team adds.

Not only gold produced

As the CERN nuclear research center explains, the high-energy collisions at the LHC can produce the quark-gluon plasma that made up the universe one millionth of a second after the Big Bang and from which matter was created. Much more frequently, however, the colliding particles would just miss each other and merely allow their electromagnetic fields to interact. This can produce photons, which in turn can knock neutrons and protons out of the atomic nuclei. To create a gold atom in this way, exactly three protons have to be removed from a lead nucleus. How often this happens has now been counted directly for the first time for the study.

For the analysis, the research group used the LHC instrument ALICE to determine in how many of these interactions none, one, two or three protons were removed from a lead nucleus, thus creating lead, thallium (atomic number 81), mercury (atomic number 80) or gold (atomic number 79). The gold nuclei were therefore formed less frequently than the thallium or mercury atoms. What they all have in common is the high energy they have immediately after their formation, which ensures that they hit an obstacle almost immediately afterwards and are fragmented into individual protons, neutrons and other particles. The tiny amounts of gold therefore only exist for fractions of a second.

Gold production on the side

The analysis now presented in the journal Physical Review C is the first systematic evaluation of gold production in the LHC, explains the research team. It was made possible by the ZDC (Zero Degree Calorimeter) detector on the ALICE instrument. The results can now be used to check the theoretical models and at the same time predict the performance and losses of particles at the LHC and future particle accelerators. According to the team, the conversion of lead into gold in this way has already been achieved before, but the main thing that has now been determined is how often this happens at the LHC.

The Large Hadron Collider is the world's largest scientific instrument and is built underground in Geneva on the border between Switzerland and France. One of the greatest scientific successes of the huge particle accelerator is the detection of the Higgs boson, which was later awarded the Nobel Prize in Physics for its prediction. Protons are shot at each other with immense energies in the long tunnel, and the connected large-scale experiments ALICE, CMS, ATLAS and LHCb then analyze exactly which particles are created during these collisions. Over years of work, new insights into the fundamental properties of our universe are then gained from the immense amounts of data.

(mho)