What is the matter we perceive in the universe made of?
First, there are the usual suspects, e.g. electronic, proton, Quark and neutrino. But if these particles aren’t weird enough for you, I can help.
There are other particles that are so rare that we’re not even sure they exist. Here are five of the strangest and rarest hypothetical particles in the universe.
dark photon
Everyone loves photons. It gets along well with many other particles. It has infinite scope. It makes the flashlight work. But it may not be the only type of photon. Enter the dark photon, which is just like a regular photon, but just…dark.
Dark photons are motivated by the following mystery dark matter and dark energy. Dark matter is an invisible form of matter that makes up most of the mass of nearly every galaxy. All told, it accounts for about 25% of the energy in the universe. Dark energy is the cause of the accelerated expansion of the universe and accounts for 70% of its composition.
One of the many questions cosmologists face is how simple or complex these dark components are. We know that regular matter is extremely complex, with a wide variety of particles and forces at work. Is the Dark Area, as it is called, vast, simple, stupid, or as rich and diverse as the light side of the universe?
If the dark area is complex, there may be additional force of nature Only between dark matter and/or dark energy, and dark photons would be the carriers of these forces. No searches have yet found any evidence of dark photons, but we still have a lot to learn.
Related: Hypothetical ‘dark photons’ could reveal mysterious dark matter
Covaton
Let’s go back to the earliest moments big Bang. Cosmologists believe that our universe went through a period of incredibly rapid expansion, called inflation. Powering this event is a mysterious substance in the universe called “inflaton” (basically like dark energy on steroids).
Inflation is still hypothetical, but it does have one strong prediction: the structure of the universe. The statistical properties of structures in our universe match what we expect from the expansion of the universe, so we believe this dramatic event was Star, galaxy and the clusters that emerged later.
Despite these successes, inflation still presents some thorny problems. For one, it’s difficult to model “natural” inflations—in the sense that they start and end without any fine-tuning—and still produce the seeds of cosmic structure. To solve this problem, some theorists have proposed a companion star to the inflaton, called a curvature.
Curvaton’s job is to sit back and wait for inflation to do its thing. Then, the curvaton steps in and lays the foundation for the structure. The advantage of this approach is that the inflation model can be more “natural” because we are not forcing one entity – the inflaton – to do all the work in the early universe.
The disadvantage of this approach is that we replace one hypothetical entity with two, which does not entirely alleviate concerns that our understanding of the entire inflation picture may be wrong. But in any case, curvaton is worth studying, because research in this direction may open up a promising avenue. Plus, it has a really cool name.
glue ball
The carrier of the strong force is a particle called glueof which there are nine varieties.
The interesting thing about gluons is that they also feel powerful forces. Therefore, our best models of protons tell us that gluons are strongly interacting thermal chaos. And they’re not the only hot topics in strong interactions. Protons and neutrons have three quarks (and gluons), and there is a whole family of particles called mesons that contain two quarks (and gluons).
So we get all these combinations of quarks and gluons, held together by the strong nuclear force. But if gluons feel the powerful nuclear force anyway, why don’t we just skip the quark part? Why make things so complicated? Just keep it simple. That’s how we came up with the glueball, which is a giant particle made up of a collection of gluons… stuck together.
What makes the glue ball so elusive is its extremely short lifespan, which lasts less than a microsecond. This is not surprising. Every combination of quarks and gluons, except protons, is also unstable in isolation. But the life of the rubber balls is expected to be very short. Otherwise, we would now be seeing them floating in our backyards.
But the predicted mass of the glueball is also within the range of almost all other composite particles. So we might be making it but not realizing it, because when we see a surprising new particle in a collider, we can usually only quantify its quality. This means that we have observed a large number of candidate glueballs since 2013, but we may also be seeing other, less exotic particles.
Today, there are complete experiments, e.g. GlueXdedicated to finding the glue ball. This is the last big prediction Standard model Still standing, so it’s worth looking for these strange particles.
X17
Ever since we invented the Standard Model of particle physics, we’ve been working hard to surpass it. In 2015, physicists at the Hungarian Nuclear Research Institute ATOMKI received a signal that something might be wrong.
The team assembled a device to search for dark photons. The device involves firing protons at lithium-7, which then transforms into beryllium-8 nuclei, which then decay and produce electron and positron pairs. The pairs fly at different angles, and scientists used nuclear physics calculations to predict the spread at these angles. If they get more of these particles than they expected, it could be because dark photons are involved.
In fact, the Hungarian team discovered extra electrons and positrons. In order to regenerate the signal, there must be a new particle with a mass of 17 MeV (34 times the mass of the electron), so this mysterious new particle got a name: X17.
Over the next few years, the Hungarian team achieved a series of impressive achievements, all of which demonstrated the reality of the new particle, including statistical significance exceeding 6 sigma, and worked with collaborators to find similar signal.
Still, most of the mainstream physics community remains skeptical of X17. All “independent” confirmations carry some sort of fingerprint from the original Hungarian team, and no one outside the network can reproduce the effect.
In addition, there are some relatively reasonable explanations for the anomalies caused by the geometry of the detector. While I hope X17 exists, I wouldn’t get my hopes up just yet, given that we haven’t seen any new evidence of this particle.
Prien
You already have your elements, like helium and aluminum. They are composed of elementary particles such as protons, neutrons and electrons. But they are made of even smaller matter: quarks. So why stop there? Perhaps what we call the fundamental particles of the universe are actually composite structures of smaller objects, known as protons (like “prequarks”, not to be confused with prions.
One of the biggest motivations for the Preson is that many particles are very similar to each other, but have only a few subtle differences. For example, electrons and positrons differ only in charge, and electrons and muons differ only in mass. We currently have no explanation for these nearly identical properties, so we suspect they may arise from some other interaction.
Preons have been proposed to explain…well, just about every outstanding question in the Standard Model, from why there are only three generations to what dark matter is. But nothing seems to stick together, and that’s because no experiments have given any hint that quarks and lepton It is a composite particle. We do everything we can to break them up, but they just continue to be themselves.