So I understand that Up and Down quarks make Protons and Neutrons so why do we bot see more of the other types of quarks around us and the various particles they compose?
In: Physics
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.
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.
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.
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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.
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.
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