Physicists have only detected a very strange particle that is not a particle


Sounds like the beginning of a very bad physics puzzle: I am a particle that really is not; I disappeared before it was even detected, but it can still be seen. I break your understanding of physics, but do not review your knowledge. Who am I?

It is an odderon, a particle that is even stranger than the name suggests, and may have been detected recently in the Large Hadron Collider, the most powerful atom-destroyer, where particles are compacted near the speed of light within a radius of 17 miles (17 miles) ring near Geneva, Switzerland.

First, Odderon is not really a particle. What we think of as particles are usually very stable: electrons, protons, quarks, neutrinos and so on. You can hold a bunch of them in your hand and carry them with you. Damn, your hand is literally made of them. And your hand is not fading in the air anytime soon, so we can probably safely assume that its fundamental particles are in the long run. [7 Strange Facts About Quarks]

There are other particles that do not last long, but can still be called particles. Despite their short lives, they remain as particles. They are free, independent, and capable of living on their own, separate from any interactions – these are the marks of a real particle.

And then there's the so-called quasi-particle, which is just one step above not being a particle of all. Quasiparticles are not exactly particles, but they are not exactly fiction. It's just … complicated. [The 18 Biggest Unsolved Mysteries in Physics]

How, literally complicated. In particular, interactions of particles at super high speeds become complicated. When two protons collide with each other almost at the speed of light, it's not like two billiard balls cracking together. It's more like two jellyfish bubbles swinging from one to the other, putting their guts inside out and having everything rearranged before they get back to being jellyfish on their way out.

In all this complicated mess, strange patterns sometimes appear. Small particles enter and exit existence in the blink of an eye, only to be followed by another fleeting particle – and another. Sometimes these flashes of particles appear in a particular sequence or pattern. Sometimes there are not even flashes of particles, but only vibrations in the soup of the collision mix – vibrations that suggest the presence of a transient particle.

This is where physicists face a mathematical dilemma. They may try to completely describe all the complicated confusion that leads to these effervescent patterns, or they may pretend – purely for convenience – that these patterns are "particles" in themselves but with strange properties such as negative masses. and spins that change over time. [5 Seriously Mind-Boggling Math Facts]

Physicists choose the last option, and thus the quasi-particle is born. Quasiparticles are short, effervescent patterns or energy ripples that appear in the midst of a collision of high-energy particles. But since it takes a lot of work to completely describe this situation mathematically, physicists take a few shortcuts and pretend that these patterns are their own particles. It is done just to make math easier to deal with. So quasiparticles are treated as particles, even if they definitely are not.

It's like pretending your uncle's jokes are really funny. It is quasifunny purely for convenience.

A particular type of quasiparticle is called Odderon, predicted to exist in the 1970s. It is believed to appear when an odd number of quarks – tiny particles that are the building blocks of matter – flash and disappear briefly during proton collisions and antiprotons. If odors are present in this crushing scenario, there will be a slight difference in the cross-sections (physical jargon for how easily one particle hits another) of collisions between particles with themselves and their antiparticles. [Photos: The World’s Largest Atom Smasher (LHC)]

So if we hit a lot of protons together, for example, we can compute a cross section for that interaction. So we can repeat this exercise for proton-antiproton collisions. In a world without odderons, these two cross-sections must be identical. But odderons change the picture-these brief patterns we call odderons appear more favorably in particle-particles than antiparticle-antiparticles, which slightly modifies the cross-sections.

The problem is that this difference is expected to be very, very small, so you would need a ton of events, or collisions, before you could claim a detection.

Now, if we had a giant particle collider that would regularly crush protons and antiprotons together, and we would do it so powerfully and so often that we could get reliable statistics. Oh, right: we do, the Great Hadron Collider.

In a recent paper published on March 26 on prepress server arXiv, TOTEM Collaboration (in the acronym for the hilarious jargon of high energy physics, TOTEM stands for "TOTAL cross section, elastic scattering and diffraction dissociation measurement in the LHC ") significant differences between cross sections of protons breaking other protons versus protons hitting antiprotons. And the only way to explain the difference is to resurrect this idea of ​​Odderon's decades. There may be other explanations for the data (in other words, other forms of exotic particles), but odderons, strangely enough, seem to be the best candidates.

Has TOTEM discovered anything new and interesting about the universe? For sure. Has TOTEM discovered a new particle? No, because odderons are quasiparticles, not particles in their own right. Does this still help us to go beyond the limits of known physics? For sure. Does the known physics break? No, because the odderons were predicted within our current understanding.

Does this all seem a little strange to you?

Paul M. Sutter is an astrophysicist Ohio State Universityhost of Ask an Astronaut and Space Radioand author of Your place in the universe.

Originally published in Living Science.


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