Annihilation - matter/antimatter

In summary, when an electron and positron collide, they release high energy photons/gamma rays. Antimatter is not the same as negative energy matter.
  • #1
jnorman
316
0
sorry for this elementary question. when an electron (matter) and a positron (anitmatter) collide, they annihilate, releasing high energy photons/gamma rays - correct?

so, when particle pairs are created within the quantum foam, which pop into and out of existence within the Planck time period, where does the annihilation energy go?

and, antimatter is not the same as a negative energy particle, correct? what is a negative energy particle?

thanks.
 
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  • #2
My understanding is that what happens is that the energy produced when two particles annihilate in the quantum foam is that it almost immediately goes into the production of two new particles. It is not a "given" that there exist "negative energy particles". I believe that they was originally postulated as "anti-particles" but I don't know what their status is now.
 
  • #3
I believe the energy you're talking about is what we refer to is vacuum energy. The non-zero expectation value of energy in a vacuum implies that even nothing has energy. If I'm wrong, please correct me.

However, I can tell you that antimatter is not the same as negative energy matter. Antimatter has positive mass, as I found out once :).
 
  • #4
well, then where does the "negative energy particle" come from which supposedly accounts for BH evaporation?
 
  • #5
benk99nenm312 said:
Antimatter has positive mass, as I found out once :).
This highly-intriguing and imagination-provoking statement (I'm picturing a Family Guy cut-away scene) will probably be much less intriguing if you actually explain it. Best entertainment value if you don't. :wink:
 
  • #6
In the bubble diagram (virtual pair production) for photons, the total mass (energy) uncertainty is dE=2m0c2 (where m0 = electron rest mass.
The Uncertainty Principle allows a dE for a duration dt = hbar/dE.

If we write hbar = λbar·m0c
where λbar is the reduced electron Compton wavelength, then

dt = hbar/dE = λbar/2c, or

c dt = λbar/2 is the length of the bubble = 1/2 reduced electron Compton wavelength = (1/2)·3.86 x 10-11 cm.

Thus the dt is the time it takes for light to travel ~ (1/2 pi) x electron Compton wavelength.

α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω
± − · × ÷ √ .
 
  • #7
jnorman said:
well, then where does the "negative energy particle" come from which supposedly accounts for BH evaporation?

The negative energy particle comes from 1 of 2 virtual particles in pair production. If a virtual pair of particles comes in, then one of them has negative energy in order to conserve the total energy of the pair (=0), I believe. The negative energy particle could be the antimatter or matter particle.

Where's George (Jones)? :smile:
 

1. What is annihilation?

Annihilation is a process in which a particle and its corresponding antiparticle collide and are converted into energy. This energy can take the form of gamma rays, which are high-energy photons, or other subatomic particles.

2. What is matter-antimatter asymmetry?

Matter-antimatter asymmetry refers to the imbalance between matter and antimatter in the universe. According to the Big Bang theory, equal amounts of matter and antimatter should have been created at the beginning of the universe. However, we observe that there is a significant amount of matter in the universe compared to antimatter. This is still an unsolved mystery in physics.

3. How is antimatter created?

Antimatter can be created in a laboratory through high-energy collisions between particles or by the decay of certain radioactive materials. It can also be produced naturally in some astrophysical events, such as supernovas.

4. Can matter and antimatter annihilate each other completely?

Yes, when matter and antimatter collide, they can annihilate each other completely, converting all of their mass into energy. This process is highly efficient, with almost all of the mass being converted into energy. This is why antimatter is often referred to as "the most powerful fuel".

5. Is annihilation used for any practical applications?

Yes, annihilation is used in medical imaging techniques, such as positron emission tomography (PET), where a positron (the antiparticle of an electron) is injected into the body and its annihilation with an electron produces gamma rays that can be detected and used to create images of the body. Annihilation is also being studied as a potential source of energy for space travel.

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