Annihilation Reactions

[ihwip]

A proton and an anti-proton annihilate each other when they meet. The problem is that they are made up of smaller particles. How do these particles react when coming in contact with each other? Does it not work this way? Would it be possible for a pair to graze each other and only annihilate a quark off of each etc?

 

[ihwip]

Anyone?

 

[Jerromy]

Annihilation in the definition of the term means that everything is "destroyed". It doesn't quite happen like that in our universe because nothing is ever gained or lost... only changed. There may very well be reactions between atoms where partial annihilation occurs and the result is different atoms and light, but that is beyond my comprehension at this time.

 

[bushwhacker]

as far as i understand this if any portion of a partical and anti partical come into contact it will all go..the particals will be destroyed but its all converted to energy so the conservation priciple still applies

 

[weeman]

Annihilation in the definition of the term means that everything is "destroyed". It doesn't quite happen like that in our universe because nothing is ever gained or lost... only changed. There may very well be reactions between atoms where partial annihilation occurs and the result is different atoms and light, but that is beyond my comprehension at this time.

You are correct. And the "change" is the transformation of matter into energy. As we learn from Einstein's formula: E=mc^2, matter and energy are two versions of the same thing: they are interchangable. When matter and antimatter annihilate they release an enormous amount of energy. The best analogy I've seen was on the TV show "The Universe" where one physicist held up two handfuls of sand. She said that if one hand represented matter, and the other represented antimatter, the energy released by the two handfuls colliding would power the entire state of California for one week!

 

[Vax]

So what you are saying is the change in matter would create energy equal to E=MC^2 or it would create greater energy?

Would the two making contact create energy equal to the mass of both the matter and the anti-matter? Or would ensteins theory only apply to one of the 2 matters? Or would they cancel each other out creating no energy? All these things defy the laws of everything, therefore I'm sure they cannot exist as unanswered questions for so long. If anyone could clear this up? What laws apply?

answer as many of these questions as you can

 

[origin]

So what you are saying is the change in matter would create energy equal to E=MC^2 or it would create greater energy?

equal

Would the two making contact create energy equal to the mass of both the matter and the anti-matter?

Yes

Or would ensteins theory only apply to one of the 2 matters?

No

Or would they cancel each other out creating no energy?

No

All these things defy the laws of everything, therefore I'm sure they cannot exist as unanswered questions for so long. If anyone could clear this up? What laws apply?

answer as many of these questions as you can

The questions followed by a 'no' do defy the "laws of everything" becasue they are wrong.

The basic problem (I think) is that you did not understand that E = mc^2 depend only on the mass and anti matter has mass.

 

[ihwip]

If a proton and an anti-proton collided, it should produce 2 photons (I think) and no other particles (possibly neutrinos?)

What I am after is how that reaction unfolds. Do the quarks inside the 'merged matter' first wipe out a pair of up quarks, then down quarks then another pair of ups, or something similar?

I am thinking that the reaction is simply that the entire things merge and annihilate because quarks don't really exist inside a proton and are instead simply the results of colliding them. Kind of like...when you slice a cake. The individual pieces are still made of cake but they have new properties like appearance, shape and probably smell in some cases.

 

[Kessy]

ihwip, the answer to your original question is that in principle, yes, individual quarks annihilate individual antiquarks when a proton and an antiproton collide. In practice, by the time the two are close enough for any of the constituent quarks to interact, the forces pulling together the rest of the quarks are so strong that there's no way for them not to come in contact and annihilate each other.

Yes, annihilation reactions do produce neutrinos in addition to photons. This is actually one reason antimatter as a power source is impractical - the neutrinos carry away a lot of the energy, making it very inefficient.

As for your question about quarks really existing or not, you should read the thread on the strong force in this forum. Because of the odd properties of the strong force, quarks are never observed as free particles, but we do have good reason to believe they exist.

 

[Jerromy]

IMO the interaction between matter and antimatter is a chain reaction, like Kessy stated, but the quark and antiquark portion seems to me to be inconclusive. As far as I have read matter and antimatter are both composed of atoms, which are composed of quarks, but there is no definite polarity to the quarks themselves to say there are quarks and antiquarks. When one delves into the subatomic level to discern various string vibrations which may or may not occupy exclusively 4 dimensions of our spacetime the details of interactions become extremely fuzzy. All we know on this side of reality is that either a reaction creates electromagnetic radiation exclusively or it creates modified molecular orientation and excitement.

To be quite honest I know more about matter-antimatter reactions chanelled through a di-lithium matrix creating a warp bubble then I do about realistic science based subatomic reactions. No one can say for sure which is fantasy and which is scientific fact.

 

[MeteorWayne]

Well, you could know more with a little research

 

[Kessy]

The thing you have to remember is that matter and antimatter are not fundamentally different things. An antiparticle is a bit like a reflection of its corresponding particle - it has the same mass, but all its other properties are equal and opposite. But all those properties can have the opposite sign in different normal particles, there is no one property you can look at and say, "Okay, this is antimatter." When a collider spits out some new exotic particle that no one's ever seen before, it can be a bit arbitrary deciding which version is the particle and which the antiparticle.

The other important thing is that particles will only annihilate with their particular antiparticle. So, nothing will happen if you shoot positrons at ordinary neutrons, and up quarks can coexist quite happily with antidown quarks. Actually, I believe (someone correct me if I'm wrong) that some of the more exotic things to come out of colliders are actually composites made up of different particles that are normally considered matter and antimatter.

And Jerromy, the Star Trek version is complete fantasy. No one in their right mind would power a ship with an antimatter reactor. For the amount of equipment you need, an ordinary fission reactor will give you about the same amount of power, and be more efficient to boot. Plus there's the small detail that antimatter is insanely dangerous to keep around in quantity...

 

[neilsox]

If one positron annihilates an electron in a gold atom, the gold atom becomes an ion with a positive charge. For a fento second there are some gamma photons inside the atom, but they depart at the speed of light, after perhaps one photon is absorbed by one of the hundreds of sub atomic particles in a gold atom. If there are trillions of gold atoms in a bulk material perhaps half of the gamma photons are absorbed, producing possibly a declining atomic chain reaction that damages most of the gold atoms but there will still be lots of debris = daughters. So it seems to me. What happens if the electron that was annihilated was one of the two in the inner shell? Do the electrons jump sequentually inward until the missing electron is in the outer shell in about one nanosecond? Neil