New particles could explain dark matter

Colors connect the world

Unlike Lego pieces, quarks don’t fit together. They need a force that can stick them together. Physicists often call this force the “color force” because it exhibits properties reminiscent of how different colors mix.

Thus, the three quarks that together make up a proton have the color forces of red, green and blue.

When light mixes with the three colors, they cancel each other out, so that the result is white light. Likewise, the color forces of quarks balance each other out, which is what is required for a proton to remain stable.

This principle applies to all particles that physicists can observe. It can only exist if the color forces of the quarks are in balance with each other.

In physicists’ catalog of particles, they all have a so-called antiparticle with an opposite color force. The opposite of “red” in this context is “anti-red”, so here the comparison with the usual colors is no longer valid.

A quark and an antiquark, for example an up quark and an anti-down quark, can form what’s called a pion, as long as the forces of color cancel each other out. All quarks and antiquarks can in fact combine two and two to make particles – even a quark with its own antiquark, although such a particle would quickly decay.

Countless experiments have confirmed the rule that color forces must equal each other, and so physicists have never seen free quarks in accelerators, for example.

It takes two or three quarks to make an observable colorless particle. However, this does not exclude the possibility of doing this also with four or five quarks.

Multiple quarks appear

In 2003, the first possible trace of a tetraquark – that is, a particle with four quarks – appeared in an accelerator in Japan. Since then, more than a dozen results have been reached – more certain – during further experiments.

In 2015, physicists at the LHC Large Accelerator at CERN in Switzerland spotted the first trace of a pentaquark – a particle made up of five quarks.

The discovery of the pentaquark was a sensation, and precisely because of this, physicists were skeptical about it.

When particles collide in accelerators, the collisions leave countless particles, which only exist for a fraction of a second, and thus it is easy to misinterpret the results.

But now new research has confirmed this discovery. Researchers at the University of Pittsburgh in the US and Swansea University in the UK went through data from the LHC experiment and count on them On the basis of a new model.

In the model, the researchers treat the pentaquarks as particles, and then it turns out that not just one, but six pentaquarks are needed to explain the LHC results.

Swansea University physicist Tim Burns said during the release: “We now have a model that nicely explains our data and, for the first time, includes all the constraints that this data provides.”

The biggest limitation of this data is that pentaquarks live so incredibly short that they cannot be seen directly.

In detectors, physicists can only see the particles in which the pentaquarks have decayed, and in some cases only the decay particles of the decaying particles. Therefore, scientists often have to count back to see if the pentagram ever existed.

New confirmation of the existence of pentaquarks shows that five quarks can be bound together using the color force. The set of color powers can be varied, but can for example consist of two colors red, one anti-red, one green, and one blue.

It will reveal the glue of the atoms

We hope that closer studies of the pentaquark and other quarks will teach researchers more about the nature of the color force.

According to the theory, the forces not only act to hold the quarks inside, say, protons and neutrons, but extend outward, so that they are also the glue that holds the atomic nuclei together. Without the color force, the positive charge in the protons of an atom’s nucleus would force them apart, causing the nucleus to disintegrate.

However, how the color force makes atomic nuclei stable is still an open question, and perhaps the multiquarks will help answer it.

Physicists expect a lot from multiquarks even on a larger scale.

One of the biggest mysteries of the universe is that it contains what appears to be unknown matter – the so-called darkness – that we cannot see. We only know that it must exist, otherwise the stars in the galaxies would not be able to rotate so quickly. The spin speed is only possible if there is a large amount of dark matter acting on the stars with its gravitational force.

Some physicists believe that the mysterious dark matter may have been composed of multiple quarks, more precisely hexaquarks – that is, particles made up of six quarks.

The research on hexaquarks has just begun, and so far only one variable has been measured in the experiment.

However, hexaquarks are more volatile than pentaquarks Physicists think They probably formed in large quantities immediately after the Big Bang.

There they probably gathered together in clouds in a special state of matter called Bose-Einstein condensates, and if they picked up enough electrons quickly, the clouds might have escaped as stable matter.

If this theory is correct, it would mean that the hexagons are invisible Lego pieces, which make up 85% of all matter in the universe.