Bosons, Hadrons, Fermions. And how they interchange with each other? (Weak force explained?)


What are bosons, hadrons, and fermions? I understand they are made up of quarks, electrons, neutrons, gluons, photons, etc. but how do they change into each other? How does a photon become an electron (I understand what I might be asking is how does the weak force work) but I’m not exactly sure?

In: Physics

So you have 2 groups by spin, fermions and bosons. Bosons have an integer spin, and fermions have 1/2 integer spin. There’s a bunch of things that come out of that distinction.

Bosons contain lots of different particles that are hard to group, photons, gluons, W and Z bosons, the Higgs, and a couple others. In Quantum Field Theory, all “force carrying” particles are bosons, called gauge bosons.

Then you can find distinctions between different fermions. Leptons, like electrons, neutrinos, and others; and quarks, (up, down, strange, charm, top, bottom).

The quarks combine in two different ways, all of which are grouped into the category of hadrons

1. By 3 quarks, or a baryon

2. 1 quark and 1 anti-quark, or a meson

Hadrons make up protons, neutrons, and other heavy objects.

> How does a photon become an electron (I understand what I might be asking is how does the weak force work) but I’m not exactly sure?

This is an extremely good question. You’re not going to get a satisfying answer to it though.

The physics explaining the process is well understood. For example, we know that in the decay of a neutron, the energy released goes into a neutrino which is instataneously created. This is a weak force interaction and so the carrier particle _is_ the neutrino.

Likewise, the force carrier for the electromagnetic force _is_ the photon. Electromagnetic interactions will involve photon creation and destruction (and more in some cases).

We can abstract this out quite a lot by forgetting the very literal view of “particles” and just thinking of the entire electromagnetic (or weak or whatever force you care about) field of the entire universe existing everywhere. This field is not flat (i.e. it does not have zero energy); it has bumps. These bumps can materialise (more exactly, can be regarded/ viewed/ observed) as particles. The field is also not static; it can change with time. The bumps or the “flat” parts of the field can flatten or bumpen. This would release/ capture energy which must necessarily involve an interaction with the _field_ itself. We have established that the field and the particles are interchangable; so anything that happens involving a change in the field necessarily will involve the appearance of particles – at least from a certain perspective.

As for exactly how the flow of energy can interact between fields and particles, etc. Well this is QFT and takes years of study to really learn and appreciate. Its simulatenously not that complicated (at least not for simple calculations and observations) while also being incredibly complicated when you actually stop and try to make meaningful sense of exactly how and why a lot of these things are happening. And really this is the story of quantum mechanics in general; the maths behind it is extremely logical, simple and elegant. But then picturing what that means for reality does make your brain hurt.