By way of the trying glass: The alchemists’ dream, it seems, was not misguided – simply untimely. Whereas the gold created by CERN researchers cannot fill vaults, it has unlocked deeper insights into the universe’s basic forces.
For hundreds of years, the transformation of lead into gold was the final word objective for alchemists, a dream fueled by the same densities of the 2 metals and gold’s enduring attract. Whereas chemistry finally revealed that lead and gold are essentially totally different components, making such a metamorphosis unattainable by chemical means, trendy nuclear physics has now realized this historical ambition, if just for a fleeting second and in vanishingly small portions.
Researchers at CERN’s Massive Hadron Collider (LHC) have reported the primary systematic experimental detection and measurement of lead transmuting into gold. The findings, printed by the ALICE collaboration in Bodily Evaluate Journals, element how high-energy physics has achieved what was as soon as the stuff of legend.
The method hinges on a phenomenon far stranger than alchemy: near-miss collisions between lead nuclei touring at 99.999993 % the velocity of sunshine. Whereas head-on collisions within the LHC famously create quark-gluon plasma – a primordial soup of particles that existed microseconds after the Huge Bang – the vast majority of interactions are much less dramatic. When nuclei narrowly keep away from colliding, their intense electromagnetic fields work together, triggering uncommon nuclear transformations.
Lead’s 82 protons generate a strong electromagnetic area, and at near-light speeds, this area compresses right into a fleeting, pancake-shaped pulse of photons. These photons can strike close by nuclei, inflicting “electromagnetic dissociation” – a course of that ejects protons and neutrons.
To forge gold, three protons should be knocked out of a lead nucleus. The ALICE staff used specialised detectors known as zero diploma calorimeters to trace these occasions, distinguishing between outcomes: zero protons misplaced (lead), one (thallium), two (mercury), or three (gold), every accompanied by not less than one neutron.
The outcomes are staggering in precision but humble in scale. Through the LHC’s Run 2 (2015 – 2018), roughly 86 billion gold nuclei have been produced – a complete mass of 29 picograms, or 0.000000000029 grams.
Upgrades in Run 3 almost doubled this output, but the quantity stays trillions of instances smaller than wanted for even a single ring.
“It’s spectacular to see that our detectors can deal with head-on collisions producing hundreds of particles, whereas additionally being delicate to collisions the place just a few particles are produced at a time, enabling the examine of electromagnetic ‘nuclear transmutation’ processes,” says Marco Van Leeuwen, ALICE spokesperson.
The gold created is not any extraordinary metallic. These ultra-high-energy nuclei survive for mere microseconds earlier than placing the LHC’s infrastructure and disintegrating into protons, neutrons, and different particles.
Whereas the achievement fulfills an historical fantasy, its true worth lies in advancing nuclear physics. The findings refine fashions of electromagnetic dissociation, that are crucial for managing particle beams. Electromagnetic dissociation is used to grasp and predict beam losses which can be a significant restrict on the efficiency of the LHC and future colliders, explains John Jowett of the ALICE collaboration.
