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In particle physics, high speed collisions are generally a good thing.
And, when two photons are smashed against each other with enough force, the output is matter, according to Einstein’s special theory of relativity. This process would produce an electron-positron pair, representing the conversion of light to mass, which seemed beyond our reach. But not for long.
Physicists have discovered a way to do this in real life using the Brookhaven National Laboratory’s Relativistic Heavy Ion Collider, which directly witnesses this reaction, known as the Briet-Wheeler process, according to a recent article published in the journal. Physical examination letters.
This is a substantial discovery, which leans on a theoretical wall that seemed insurmountable only a few decades ago.
Acceleration of gold ions to almost the speed of light
“In their article, Breit and Wheeler already realized that it was almost impossible to do,” said Zhangbu Xu, a physicist at Brookhaven Lab, of the two scientists who initially described the process, in a blog post at the official website of the laboratory. “Lasers weren’t even there yet! But Breit and Wheeler came up with an alternative: accelerating heavy ions. And their alternative is exactly what we’re doing at RHIC.” Accelerated ions refer to the increase in the speed of atomic nuclei that have been stripped of electrons. Since the latter have a negative charge and the remaining protons in the nucleus of the atom retain a positive charge, this makes the heavier elements directly proportional to a larger positive charge, since it contains more protons without electrons. .
The researchers in this recent study used gold ions, which have 79 protons. It’s such a strong charge that, when accelerated to ridiculous speeds, the gold ions generate a circular magnetic field that rivals the perpendicular electric field in the collider. When these two fields intersect, they can lead to the generation of electromagnetic particles, also called photons. “So when the ions move near the speed of light, there is a bunch of photons surrounding the gold core, traveling with it like a cloud,” Xu said in the blog. RHIC accelerates ions at relativistic speeds, which is a substantial fraction of the speed of light. Recent experience has seen gold ions accelerated to a mind-blowing speed of 99.995% of the speed of light. It’s very, very fast.
Physicists have detected several properties of a Breit-Wheeler process
And, when two ions are barely missing, their two clouds of photons begin to interact and even collide. These encounters occur without detection, but the reaction efficiency of the electron-positron pairs can. But this is not enough, as the photons generated via this electromagnetic interaction are simply virtual in nature – swelling in and out of existence and without the measurable “real” mass of their physical counterparts. To satisfy the conditions for a full bore Breit-Wheeler process, two “true” photons must break into another true pair of photons. Fortunately for physicists today, there is a technical way to differentiate between virtual electron-positron pairs and the true Breit-Wheeler chord: the angles between the positron and the electron in the pair produced by the high-speed collision. .
And physicists have detected several different properties of real photons, including the systems’ energy, mass distributions and quantum numbers, according to Daniel Brandenburg, a physicist at Brookhaven Lab, in the blog. “Our results provide clear evidence for the direct one-step creation of matter-antimatter pairs from light collisions, as originally predicted by Breit and Wheeler.” This is an extremely compelling discovery, with an upcoming challenge of detecting the photon-photon process directly by shattering photons with gamma ray energy.
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