Question on whether positron/Down Quark can be fused.

[42supernerd]

I was wondering that if positrons are antimatter and Down Quarks which are regular could be pushed together so that they break down into energy? The second question is whether this could be used for a form of fusion or fission reaction which ever is more accurate in this case by breaking a proton into 2 high energy free quarks and the energy of the first reaction?

 

[Simon Bridge]

Welcome to PF;

if positrons are antimatter and Down Quarks which are regular could be pushed together so that they break down into energy?

I'd be surprised - positrons annihilate electrons. A down-quark would annihilate an anti-down quark.

Technically a positron could get captured by an anti-proton to make an anti-neutron, releasing a photon.

For a reaction to count as fission you have to end up with at least two nuclei, to count as fusion you have to start with at least two nuclei and end uo with at least one bigger one. Your examples don't count as either since they don't involve nuclei at all.
In general, matter-antimatter reactions are neither fusion nor fission - they are their own kind of reaction called "annihilation".

You do not get "free quarks" - at best you can have them in pairs as mesons, triples as nucleons, or as a quark-gluon plasma.
Ejection of a meson from a nucleus is possible but iirc is never spontaneous - something else has to happen too.

Does that answer your questions?

 

[42supernerd]

yes that does thanks.

 

[mfb]

The reaction positron + down-quark to electron-antineutrino + up-quark is possible via the weak interaction. This is not an annihilation process, but it could transform a neutron into a proton.

 

[42supernerd]

So if that is what happens to a neutron then what about the proton wouldn't it then be broken apart and the mesons annihilate giving of energy that would ether break apart an atom of large size or escape into its surroundings.

 

[Simon Bridge]

If that (positron+down-quark) happens to a neutron in an atom, then the atomic number goes up one. The new nucleus follows the rules for that atom. if it turns out to be unstable then it decays normally. This sort of thing happens all the time.