A particle never seen before has revealed itself in the hot intestines of two particle collisions, confirming a half-century-old theory.
Scientists predicted the existence of the particle, known as the odderon, in 1973 and described it as a rare, momentary amalgamation of three smaller particles known as gluons. Since then, researchers suspect that the odderon may occur when protons collide at an extreme speed, but the exact conditions that would cause it to remain a mystery. After comparing the data of the Large Hadron Collider (LHC), the 17-mile-long (27-kilometer) annular atomic breaker near Geneva, known for the discovery of the Higgs boson, and the Tevatron, is a narrow closed 3.9-mile-long (6.3 km) U.S. collision that struck protons and their antimatter twins (antiprotons) together in Illinois until 2011, researchers report conclusive evidence of the existence of the odderon.
Finding the odderon
This is how they found it: After the particle collisions, the scientists watched to see what happened. They thought that odderons would occur at a slightly different rate in proton-proton collisions and proton-antiproton collisions. This difference is shown in a slight mismatch between the frequencies of protons bouncing off other protons and the frequencies of protons bouncing off protons.
The LHC and Tevatron collisions occurred at different energy levels. But the researchers behind this new article have developed a mathematical approach to comparing their data. And this yielded this graph, which they called the ‘money plot’:
The blue line, which represents proton-antiproton collisions, does not align perfectly with the red line that represents proton-proton collisions. The difference is the sign of the odderon – shown with 5 sigma statistical significance, which means that the chance of an effect like this appearing randomly without odderons being involved will be 1 in 3.5 million.
Why Proton Collisions Create Odderons
So, what are odderons? Fundamentally, it is a rare combination of three “sticky” particles known as gluons.
Protons are not fundamental, indivisible particles. On the contrary, they consist of three quarks and a lot of glue. These quarks are the heavy hits of the subatomic world, relatively bulky and responsible for the mass of protons and neutrons (and in turn also the largest mass of atoms) and electromagnetic charge. But the gluons play just as important a role: they carry the strong force, one of the four fundamental forces of the universe, which is responsible for the “sticking” of quarks into protons and neutrons, and then they bind those protons and neutrons. are atomic nuclei.
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When protons collide with super-high energies within particle collisions such as the LHC, they shatter into pieces about 75% of the time. The remaining 25% of the time they bounce back like pool balls on a pool table. In this case – a process called elastic scattering – the protons survive the encounter. And physicists think this is possible because the protons exchange two or three gluons. At the short point of contact, the set of gluons moves from one proton to the inside of the other.
“In high-energy physics, we always exchange particles when two protons interact, or a proton and an antiproton” interact, “said lead author Christophe Royon, a physicist at the University of Kansas. to WordsSideKick.com. “In most cases, it will be one glue.”
It is important that proton-proton collisions and proton-anti-proton collisions exchange particles, because it is in the subtle difference between the two types of exchanges that the odderon is revealed.
Sometimes a quasi-state called a glueball – a pair or a trio of gluons – occurs during a collision. Scientists have already confirmed the existence of the double glueball, but this is the first time they have confidently seen the triple glueball called Odderon, the one predicted in 1973.
These gumballs keep protons intact because of a property called color. Colors (and anti-colors) are similar to positive and negative electromagnetic charges – they control how quarks and gluons attract or repel each other in a system much more complex than electromagnetism, known as quantum chromodynamics. Quarks and gluons can have one of three charges classified as red, green or blue. And it is said that a combination of red, green and blue is ‘white’ and therefore balanced.
Antiquarks, meanwhile, have anti-colors – anti-red, anti-green and anti-blue – which are canceled with their peers in color to form stable, balanced white charge. And gluons have both colors and anti-colors.
But individual glue is always an unstable mixture of color and color: blue and anti-green, or red and blue, and so on. ‘Every gluon has a color and a color. [these gluons] do not like to be alone, ‘said Royon.
When a single gluon enters a new proton, it grabs onto the other particles – the quarks and gluons that make up the proton. The single gluon attempts to couple with particles that balance the color and anti-color. But the colors inside the proton are already in balance, and the entrance of a strange, unstable gluon disturbs the internal balance of the proton, causing a cascade of events that tear the particle apart. This is what happens in 75% of collisions when protons shatter.
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But in a quarter of the cases where the protons bounce off each other instead of crushing, it is a sign that the gluon exchange involves a double or triple glueball (odderon) and it therefore does not have the protons’ internal balance do not interrupt. Double gumballs have their own internal balance. Their color and counter-color charges are matched and slide easily from one proton to another without tearing them apart. In 1973, researchers showed that three gluons could theoretically form a triple glueball in which red, green, and blue colors balance each other. They call the particle the odderon.
Gluon and multigluon exchanges take place for the shortest moments with the utmost energy. Until now, no one has ever seen or detected an odderon directly (or the double glueball, as far as its existence has been indirectly confirmed).
The detection of the Odderon will not change the appearance of physics, as SUNY Stony Brook astrophysicist Paul Sutter wrote in an article for Live Science in 2019, when researchers first saw possible evidence for the particle. Sutter and many other researchers argue that it is not a real particle at all, but a brush particle, because it is nothing more than a temporary arrangement of smaller particles. (However, the same can be said of protons and neutrons.) Royon said the discovery is important because it confirms that the basic ideas about particle physics that researchers used to predict the existence of the odderon in 1973 were correct.
Originally published on Live Science.