Why do we mainly see particles made of Up and Down quarks, despite there being 6 types? #QuarksExplained
The Basics of Quarks
Quarks are fundamental particles that make up protons and neutrons. There are 6 types of quarks, but why do we primarily encounter particles made of Up and Down quarks?
The Dominance of Up and Down Quarks
It is true that Up and Down quarks are the most common due to their stability and interaction frequencies. This results in a majority of the particles around us being composed of Up and Down quarks.
Evidence in Particle Physics
Particle colliders and experiments have shown that Up and Down quarks are the most prevalent in nature, which explains why we mainly see particles made of these quarks.
Limits of Detection
It is also possible that other types of quarks and particles exist, but they might be harder to detect or have shorter lifespans, making them less observable in our everyday interactions.
In conclusion, while there are 6 types of quarks, the dominance of Up and Down quarks in forming particles around us is due to their stability and prevalence. #QuarkDiversity #ParticlePhysics101
The other flavours of quark are basically higher energy versions of the Up and Down quarks that atomic nuclei are made from. In our universe, systems, including particles, tend toward the lowest available energy state. So, if a high-energy quark forms, it will eventually decay into a lower-energy version. That’s why we don’t usually see particles made from these other flavours of quark. Even when they do form, through some high-energy event or whatnot, they’ll eventually transform into protons or neutrons.
Everything in nature likes to be in the lowest energy state it can, and this goes extra for nuclear physics.
So, if a particle CAN decay, it WILL decay. And it so happens that all the heavier quarks can decay into other products in normal circumstances, but Up and Down can’t because they’re already the lowest energy states.
So they’re the only two we observe.Â
Now, it is theorised that there can be stable matter with the Strange quark in the hearts of neutron stars, and that it can remain stable outside of it if it escapes, but this was not yet observed as of today.
As others have said, those four extra quarks are higher energy versions of the up and down. If you take a look at the standard model you will find that the very same works for electrons, which are the “base version” of muons and tauons. Only with their neutrinos it is a bit different, they can even turn into each other. In general the higher variants decay rather quickly into the base forms, hence why they are rarely around.
So in short: there are two base quarks (up, down), and two basic leptons (electron, e-neutrino). Each has three “variants”, plus all have anti-particles. Stuff prefers to be basic.
Plus the force carriers, which also somewhat group together under electro-weak unification/the Higgs mechanism (except gluons, and hypothetical gravitons… yet). But that’s another story.
The answers are incorrect. They don’t explain why neuron exists. Neutrons will decay into protons after 15 minutes. If you put a neutron into a nucleus, then it will be able to occupy lower energy levels and interact with the rest of the nucleus by the strong force. Now, it can’t decay into a proton because that would require going into a higher enegry shell and overcoming electric repulsion. For other quarks, this effect is too small to overcome the bigger mass difference.
A long answer, but it is needed because people are wrong.
There are 2 elements to this
a) What light barions do we have?
b) How can they be stable inside a nucleus?
Starting with 1. There are 6 types of quark. Also, the quarks can have either the spins aligned in all the same way (total spin is 3/2) or one in a different way the others (total spin in 1/2). Additionally, if all your quarks are the same then you cannot have a spin equal to 1/2 due to parity/Pauli principle.
Configuration with 3/2 spin requires more energy than with a spin 1/2
By itself, the up quark is the lightest (and the mass difference is smaller than the mass of an electron so each quark should decay into an up quark) but you can’t have a quark that is not a part of a hadron or mezon. So a neutron (udd) will decay into a proton (uud) but this will not decay into a delta+ (uuu) because that would require changing the total spin to 3/2, which costs more energy than you get from the mass difference.
But why there are neutrons?
To answer that question I will introduce the shell model of a nucleus. Inside we have hadrons moving in some potential (generated by all of them) and there are various shells each with a different energy (this is also why helium 4 is so stable, it has 2 protons and 2 neutrons so they all fit on the lowest energy shell). Because neutrons are not protons they can occupy the same shells and the electrostatic force does not repeal them because they don’t have a charge. So the nuclear binding force might make the neutron stable inside the nucleus.
This doesn’t happen to other hardons because the nuclear binding force is not strong enough to stop them from decaying even inside. Stange quarks are too massive, 3/2 particles are too massive