Physicist discovered Proof of Making Matter From Colliding Light/Photons

According to theory, on the off chance that you smash two photons together hard enough, you can generate matter: an electron-positron pair, the conversion of light to mass according to Einstein's theory of special relativity.

 It's called the Breit-Wheeler process, first laid out by Gregory Breit and John A. Wheeler in 1934, and we have awesome reason to trust it would work.

 

However, direct observation of the unadulterated phenomenon including just two photons has remained elusive, mainly because the photons need to be very energetic (for example gamma rays) and we don't have the innovation yet to construct a gamma-ray laser.

 Presently, physicists at Brookhaven National Laboratory say they've discovered a way around this stumbling block using the facility's Relativistic Heavy Ion Collider (RHIC) - resulting in a direct observation of the Breit-Wheeler process in real life.

 "In their paper, Breit and Wheeler already realized this is almost impossible to do," said physicist Zhangbu Xu of Brookhaven Lab.

 "Lasers didn't exist yet! Be that as it may, Breit and Wheeler proposed an alternative: accelerating heavy ions. And their alternative is exactly what we are doing at RHIC."

Yet, what do accelerated ions have to do with photon collisions? Well, we can explain.

 The process involves, as the collider's name suggests, accelerating ions - atomic nuclei stripped of their electrons. Because electrons have a negative charge and protons (within the nucleus) have a positive one, stripping it leaves the nucleus with a positive charge. The heavier the component, the more protons it has, and the stronger the positive charge of the resulting ion.

 The team used gold ions, which contain 79 protons, and a powerful charge. At the point when gold ions are accelerated to exceptionally high speeds, they generate a circular magnetic field that can be as powerful as the perpendicular electric field in the collider. Where they intersect, these equal fields can deliver electromagnetic particles, or photons.

 "So, when the ions are moving close to the speed of light, there are a lot of photons surrounding the gold nucleus, traveling with it like a cloud," Xu explained.

 At the RHIC, ions are accelerated to relativistic speeds - those that are a significant percentage of the speed of light. In this test, the gold ions were accelerated to 99.995 percent of light speed.

 This is the place where the magic happens: When two ions just miss each other, their two clouds of photons can interact, and impact. The collisions themselves can't be distinguished, however the electron-positron pairs that result can.

 However, it's insufficient to just identify an electron-positron pair, either. 

That's because the photons created by the electromagnetic interaction are virtual photons, popping momentarily all through existence, and without the same mass as their 'real' counterparts.

 To be a genuine Breit-Wheeler process, two real photons need to impact - not two virtual photons, nor a virtual and a real photon.

 At the ions' relativistic speeds, the virtual particles can behave like real photons. Thankfully, there's a way physicists can tell which electron-positron pairs are generated by the Breit-Wheeler process: the angles between the electron and the positron in the pair generated by the collision.

 Each kind of collision - virtual-virtual, virtual-real and real-real - can be distinguished based on the angle between the two particles created. So the researchers identified and analyzed the angles of more than 6,000 electron-positron pairs generated during their examination.

 They tracked down that the angles were consistent with collisions between real photons - the Breit-Wheeler process in real life.

"We also measured all the energy, mass distributions, and quantum numbers of the systems. They are consistent with theory calculations for what would happen with real photons," said physicist Daniel Brandenburg of Brookhaven Lab.

 "Our results provide clear evidence of direct, one-step creation of matter-antimatter pairs from collisions of light as originally predicted by Breit and Wheeler."

 The argument could be reasonably made that we will not have a direct first detection of the unadulterated, single photon-photon Breit-Wheeler process until we impact photons approaching the energy of gamma rays.

 Nevertheless, the team's work is profoundly convincing stuff - at the exceptionally least, it shows that we are barking up the right tree with Breit and Wheeler.

 We'll be proceeding to watch this space, avidly.

 The research has been published in Physical Review Letters.