LHC near-miss collisions turn lead into gold

Here is more detail and background by scientists on their Midas touch experiment!

I guess, I have so far missed the critical part of this experiment: Gold was produced not be a direct collision of atoms, but by a near miss of atoms.

"... the ALICE experiment examined the Midas touch happening inside the Large Hadron Collider: lead ions transmuting into thallium, mercury and gold.

Scientists have been able to transform heavy elements into gold using particle accelerators since the 1940s. This result was unique because it was the first time scientists had seen new chemical elements appearing in a type of collision in which the two nuclei never actually came into contact—a Midas touch without the touch.  ...

ALICE is designed to study quark-gluon plasma, the hottest and densest form of matter in the universe. ...

But only head-on lead-lead collisions in the LHC have the energy to produce a quark-gluon plasma. The majority of particle interactions during the LHC’s lead-ion run—more than 98%—result from what are actually near misses. 

In those cases, even though the two nuclei never touch, strange things can still happen.

While lead atoms are neutral, the lead ions inside the LHC have been stripped of all their electrons so that only the bare nuclei collide. This means there is nothing to balance out the ions’ 82 protons, whose whopping positive charge generates an extremely strong electromagnetic field. This field is even more concentrated by the LHC’s extreme speeds and effects of Einstein’s special relativity, which compresses the ions into pancakes.

“This compression is so strong that the resulting magnetic and electric fields are the strongest known in the universe, although they act only over very short times,” ...

When two lead ions cross paths, their electromagnetic fields can produce photons. If a photon from one lead nucleus is absorbed by the other lead nucleus, it can pop out several neutrons and—if the energy is high enough—protons.

Losing neutrons only changes the isotope of the lead (that is, they are still lead nuclei but have a new atomic weight). But losing protons fundamentally transforms the lead into an entirely new element. One lost proton transforms lead into thallium; two lost protons, mercury; and three lost protons, gold. ..."

LHC near-miss collisions turn lead into gold | symmetry magazine "In a recent study, ALICE scientists measured the way that lead ions colliding in the LHC sometimes transform into gold and other new nuclei. "