Positronium Decay: Energy of Photon?

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In summary, the decay of positronium results in the production of two or more gamma rays, each with an energy of 511 keV. This is due to the annihilation of an electron and a positron with a combined mass of 1022 keV. However, if the binding energy of positronium is taken into consideration, the energy of each photon will be slightly lower than the rest mass of an electron due to the negative contribution of the binding energy.
  • #1
integrale2
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Hi, i would like about the decay of positronium (a electron and a positron going around the center of mass) in 2 photons: if i suppose the positronium decays at the rest, what is the energy of photons?
I think that the energy of a photon is the same of mass of rest of electron, because the binding energy of positronium is very small with respect to mass of electron at the rest.
If i would like to not neglect the binding energy of positronium, what is the nergy of photon?
Thanks
 
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  • #2
translation:

Hi, i would like [to know?] about the decay of positronium (a[n] electron and a positron [orbiting their] center of mass) in[to] 2 photons: if i suppose the positronium decays [while] at ... rest, what is the energy of [the resulting] photons?
I think that the energy of [each resulting] photon is the same [as the rest] mass ... of [the] electron, because the binding energy of positronium is very small with respect to [the rest] mass of [the] electron...
If i would like to [take into consideration] the binding energy of positronium, what is the energy of [each] photon?
Thanks
http://en.wikipedia.org/wiki/Positronium
Annihilation can proceed via a number of channels each producing one or more gamma rays. The gamma rays are produced with a total energy of 1022 keV (since each of the annihilating particles have mass of 511 keV/c²), the most probable annihilation channels produce two or three photons, depending on the relative spin configuration of the electron and positron. A single photon decay is only possible if another body (e.g. an electron) is in the vicinity of the annihilating positronium to which some of the energy from the annihilation event may be transferred. Up to five annihilation gamma rays have been observed in laboratory experiments[5], confirming the predictions of quantum electrodynamics to very high order.
 
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  • #3
Hi, thanks for the translation, but I think it is a mistake to eliminate around: "an electron and a positron [orbiting] AROUND their center of mass...
In "http://www.wordreference.com/definition/orbit", i find this example: "The moon orbits AROUND the Earth"...
and what do you think from a physical point of view about:
"If i would like to take into consideration the binding energy of positronium, what is the energy of each photon?"
 
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  • #4
integrale2 said:
I think that the energy of a photon is the same of mass of rest of electron, because the binding energy of positronium is very small with respect to mass of electron at the rest.
If i would like to not neglect the binding energy of positronium, what is the nergy of photon?
Thanks

Before decay, the energy is

[m c2 for electron] + [m c2 for positron] + [binding energy]

Afterwards, we have

2 x [energy of one photon]

Since you know all quantities in the equation except the photon energy, it can be solved. If you're still stuck, post again.
 
  • #5
Hi, I am in complete agreement upon which you wrote, I still have a little doubt, that is the core of my dilemma: the binding energy of course must be considered negative and then the energy of a photon is slightly lower the rest mass of electronics. E 'right?
 
  • #6
Yes, that's right.
 

Related to Positronium Decay: Energy of Photon?

1. What is positronium decay?

Positronium decay is the process in which a positron and an electron, both with opposite charges, combine to form a bound state. This bound state is called positronium and it is unstable, meaning it eventually decays into energy.

2. How does positronium decay occur?

Positronium decay occurs through the annihilation of the positron and electron, resulting in the production of two or more photons. These photons carry away the energy of the positronium, causing it to no longer exist as a bound state.

3. What is the energy of the photon produced during positronium decay?

The energy of the photon produced during positronium decay can vary, but it is typically in the range of 1022 keV to 511 keV. This energy is determined by the mass of the positron and electron, as well as their relative velocities.

4. How is the energy of the photon related to the mass of the positron and electron?

The energy of the photon is directly related to the mass of the positron and electron through the famous equation E=mc², where E is energy, m is mass, and c is the speed of light. As the mass of the particles increases, so does the energy of the photon produced during positronium decay.

5. How is positronium decay important in scientific research?

Positronium decay is important in scientific research because it is a rare example of matter-antimatter annihilation and provides insights into the fundamental laws of physics. It also has applications in areas such as astrophysics, material science, and medical imaging.

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