If they’re all around us, why is it we need a high energy particle accelerator to detect them? From watching videos on YouTube, my understanding is each cubic meter is full of sub atomic particles, yet in order to detect them, the large hadron collider is necessary?
Edit: To clarify, my question is more around why is the collision of particles in the LHC necessary – as in why can’t the detectors that detect the output of collisions not directly observe the particles themselves?
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It’s kinda in the name, sub atomic. It’s smaller than an atom. It’s not possible to view with the naked eye
It’s not full of them. Everything around is a field that these particles can interact with. In a perfect vacuum there will be all the fields present, but no particle.
Imagine a 2D version: a wall full of buttons. If you press one, the button will glow.
Only by your fingeri nteracting with one of the buttons, it will light up, even if they all were present all the time.
That’s a field. A room where particles in the universe can interact with, but what is not activated as long as nobody does so.
We needed the halddoj collider to split all these particles from atoms and try to detect them by measuring these particles.
The particles that the LHC (and other colliders) are studying are only detectable when you smash apart protons. In nature, they don’t often collide, much less collide hard enough to be broken apart.
The Higgs Field exists all around us, and as a result the Higgs mechanism which gives certain particles their mass. The Higgs Boson is a particle created as a result of the Higgs Field, and its existence serves as evidence of the Higgs mechanism. In order to create a Higgs Boson that can be observed, you have to pack a ton of energy into a small enough space, so that that energy can be converted into the mass of the Higgs Boson. And the Higgs Boson will only get created some of the time, as there are other possible interactions that can occur when you slam protons into each other at high energies (as the LHC does). So you need high energy events and a lot of of them to get a signal of the Higgs Boson. These energies (13 TeV is the maximum energy of the LHC) are much higher than what we experience day-to-day, so not many Higgs Bosons are being created in the space around you at any given time.
Furthermore, once we’ve created a Higgs Boson, how do we actually detect it? Remember, when you see something with your eyes, you’re not directly interacting with it. Rather, light is bouncing off the object and then hitting your eyes, where it is converted to electrical signals that your brain can interpret. Similarly, with a Higgs Boson, we don’t have a type of material that automatically lights up whenever a Higgs touches it. We have to observe it indirectly through its decay products. It has a very short lifetime, after which it decays into particles such as photons, muons, electrons, hadrons, etc. And fortunately we do have ways to directly detect most of these, like electromagnetic calorimeters which absorb photons and electrons and convert their energy into an electrical signal that we can record in our computers. So this is how we actually “see” a Higgs Boson.
TLDR; You need high energies to produce Higgs Bosons, which the LHC does by accelerating protons and smashing them into each other. And to detect them, you have to look at its decay products, so you need detectors that can observe those decay products. This is what the major LHC experiments like CMS and ATLAS are for.
The LHC is a laboratory. It is using specialized equipment and specific atoms, for what they are working with (isolating atoms and creating specific collisions to observe specific outcomes) this is simply what it takes to get the job done. Atomic forces are ridiculous, equally so the equipment to corral them.
The particles being detected don’t always exist in a particle state. These experiments both generate and detect them.
The Higgs Boson is not abundant and not all around us is the simple explanation. That particle decays almost instantly and could only ever exist when a certain particle collision happens.
These particles don’t tend to hang around naked, they are busy being part of something bigger like protons. The particle accelerator smashes things together with such tremendous energy that the things you smashed break apart and their inner bits smush together into different particles. Not like you mix egg and flour to get cake, but like shooting a gigavolt up a chicken’s butt so it turns into a duck, physics is wild like that. The higgs is a big elementary particle, it’s like an over inflated pimple in the fabric of reality, holding a ton of energy, and the universe doesn’t like that just hanging around so it very quickly (fractions of a fraction of a fraction of a second) decays (transforms) into other particles that have less energy/mass. We can detect when the pimple pops and all the subatomic puss (quarks, photons, etc) oozes over the detectors around the collision point of the collider, and that’s how we detect the higgs boson.
Think about 200 years ago and knowledge of microscopic life. If you don’t know it’s there, and don’t have the tech to find out. How the hell would you know?
The Higgs Boson the LHC was built to detect does not exist everywhere. At least not in the same sense that you’re swimming around in photons and quarks and electrons or whatever.
In Higgs Physics the Higgs Field is everywhere, and the Higgs Boson is the result of the Field moving in some particular way. The Higgs Field can move in several different ways, and so there are actually 4 Higgs Bosons. 3 of those Higgs Bosons “mix” with particles in the Electroweak field, resulting in the weak bosons (W & Z), and the Photon. Yes that photon. The 4th Higgs Boson takes a fuckload of energy to produce, but it can actually be isolated, unlike the others (or at the very least you can math out that it quickly decays into some Charm Quarks in very rare cases so if you run the experiment with a fuck load of energy a fuck load of times you should see an excess of Charm Quarks in the data).
When scientists came up with the idea for the Higgs Field, they weren’t just suggesting new particles that could make things work out nicely, they basically looked at the math of how we understood things to work and said “if this fixed parameter was actually a kind of field, then it would imply these other terms would exist and that would explain a lot,” and then people looked into that and found “if this fixed parameter was actually a kind of field, then these particles should also exist.” The theory made a prediction, and that prediction is “this particle should exist.”
The Higgs particle the LHC was meant to detect isn’t a particle that’s responsible for any part of your tangible experience with the world, it’s a particle that, when detected, confirmed the existence of some other particles that are part of your experience. The every day photon is a result of the Higgs Field interacting with the Electroweak field, but I don’t think it’s practically possible to separate them, so we still think of the photon as being fundamental.
Source: Very interested lay-person, some of my details are probably wrong, but the broad strokes here should be more-or-less correct. I have a degree in chemistry, not physics.
Higgs boson and other subatomic particles are fundamental parts of atomic structures. They are so small and hard to differentiate from everything around them. The LHC speeds up particles by accelerating them in a circle surrounded by magnets to 99.999% the speed of light. Then smashes them to try to separate their parts from each other. It requires a large amount of energy and space to get enough fuel fast enough to measure differences after the collision.
Hi there! I worked at Fermilab for a while and can add something that hasn’t been listed below yet.
The biggest problem is in the way you framed the question: “as in why can’t the detectors that detect the output of collisions not directly observe the particles themselves?”
The ELIF on that is that the particles don’t exist. It’s not like you’re surrounded by them all the time. The colliders use enormous amounts of energy to create them and then the detectors detect them.
The Explain Like I’m Fifteen version is that the detectors don’t even detect most of the interesting particles. They detect energy variances or decay particles that imply the existence of the interesting particles. The Higgs, for example, decays in 1.6 x 10^(-22) seconds. When it decays it leaves behind lots of other particles that can be directly detected by the detectors. By looking at the decay energies it’s possible to reconstruct the parent particle that spawned them.
Higgs Bosons only have a lifetime of about 1.6 x 10**^(-22)** seconds.(That’s 0.00000000000000000000016)
On top of that, they’re only created during specific kinds of particle collisions, and not every time either.
Additionally, there are trillions of particles in any given cubic centimeter of open air, so good luck telling it apart from the background.
That’s why we built the LHC, We made a huge vacuum tube, i.e. a tube with no other particles flying around, and then we can smash two specific particles together at a specific speed, at a specific point where we set up detectors, so that we can see what the particles break apart into without any background noise drowning it out.
Imagine the higgs field as a still surface of a pond. We hypothesize its there but how can we prove it. We prove it by throwing rocks at it and watch/study the splash. That’s what the LHC kind of do. They throw rocks in the higgs field and we observe the splashes. The higgs boson are the splashes produced by us throwing the rocks.