Is Proton-Antiproton Annihilation Energy Conservation Still a Mystery?

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Discussion Overview

The discussion revolves around the energy conservation in proton-antiproton annihilation, particularly questioning whether the observed energy outputs align with theoretical expectations. Participants explore the implications of energy conservation laws in high-energy particle collisions, focusing on the final states produced and the energy of the resulting particles.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes a discrepancy in the expected energy output from proton-antiproton annihilation, suggesting that the total energy of the resulting photons is less than the initial energy input.
  • Another participant questions the energy contribution of the produced pion (π0) in the annihilation process.
  • It is mentioned that the rest mass of the pion should be included in the energy calculations, leading to further questions about the total energy expected from the collision.
  • Some participants propose that the pion must possess kinetic energy to account for the total energy balance in the annihilation process.
  • There are repeated inquiries about the expected kinetic energy of the pion and its relation to the overall energy conservation in the event.
  • One participant expresses a belief that the phenomenon of annihilation requires further study and data for better understanding.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the energy outputs from proton-antiproton annihilation are fully understood or if further investigation is needed. Multiple viewpoints regarding the energy contributions of the pion and the overall energy balance remain present.

Contextual Notes

Participants highlight potential missing assumptions in their calculations and discussions, particularly regarding the kinetic energy of the pion and the total energy expected from the annihilation process. The discussion reflects uncertainty about the completeness of current understanding in this area of particle physics.

Deepak247
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I recently checked this link...

http://en.wikipedia.org/wiki/Proton_antiproton_annihilation

It says that...For proton-antiproton annihilation at 2 GeV, one final state result is

p + p → π0
+ γ1 + γ2 + γ3 + γ4

with γ1 and γ3 ~125 MeV each, γ2 and γ4 ~530 MeV each

but if we add up all the MeV, then it is less than what should be the resulting energy...isnt it?

I mean all the photons will add up to make 1280 MeV, also it is happening at 2 GeV so it should definitely produce more energetic photons following the law of conservation of energy...


Are the scientists today still confused about this whole annihilation process? do they still need more study? please explain
 
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What about the energy of the π0?
 
The rest of the energy is conserved in the produced pion.
 
but the rest mass of pion π0 is 134.9766(6) MeV/c2, add this to 1280 and we get 1414.9 MeV...I was expecting something worth more energy out of this collison...does that should be the case?
 
Deepak247 said:
but the rest mass of pion π0 is 134.9766(6) MeV/c2, add this to 1280 and we get 1414.9 MeV...I was expecting something worth more energy out of this collison...does that should be the case?

Does the pion have kinetic energy?
 
please explain drakkith...or anyone else...you can refer to the above mentioned page at the start of this thread...

I still believe that this phenomenon of annihilation needs more discoveries and data to be explained well...

Does everyone agree with me or am i not getting it right?

please reply
 
The π0 has whatever kinetic energy it takes to make up the necessary total.
 
ok...just one more thing...how much kinetic energy do you expect it to have?
 
Deepak247 said:
ok...just one more thing...how much kinetic energy do you expect it to have?

More than the rest energy of a breadbox? Sorry, I couldn't help myself.
 
  • #10
Deepak247 said:
ok...just one more thing...how much kinetic energy do you expect it to have?

Unless other particles are produced, it will have whatever energy is left over as kinetic energy.
 
  • #11
Thank you so much everyone...

I got almost all the answers i was looking for

just one slight thing, if anyone still bothers to reply...

how much energy is usually observed with this π0 particle? (i.e in MeV if possible)
 

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