What is the energy equivalent of a proton-antiproton pair?

  • Thread starter Thread starter dandy9
  • Start date Start date
  • Tags Tags
    Energy
Click For Summary

Homework Help Overview

The discussion revolves around the energy equivalent of a proton-antiproton pair, specifically focusing on the calculations related to the mass-energy equivalence and the energy required for pair production involving gamma rays.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the calculations for the energy equivalent of a proton's mass and express confusion regarding the energy required for proton-antiproton pair production. Questions arise about the meaning of "g ray" and its connection to gamma rays, as well as how to apply E=mc² to the combined mass of the proton and antiproton.

Discussion Status

Some participants have provided clarifications regarding the terminology and concepts, such as the nature of gamma rays and the process of pair production. There is an acknowledgment of varying levels of understanding among participants, and the discussion is exploring multiple interpretations of the problem.

Contextual Notes

Participants mention the need to consider the reaction partner in the context of pair production, indicating that there may be additional complexities not fully addressed in the original question. There is also a note about the conversion between MeV and GeV, highlighting potential gaps in understanding related to energy units.

dandy9
Messages
27
Reaction score
0

Homework Statement


The mass of a proton is 1.67 multiplied by 10-27 kg.

(a) Find the energy equivalent of the proton's mass in joules.
(b) Convert this value to eV.
(c) Find the smallest total g ray energy that could result in a proton-antiproton pair.

Homework Equations


Einstein's famous E=mc^2

The Attempt at a Solution


I figured out (a) and (b), but am absolutely clueless as to how to approach (c). What is a "g ray"? Thanks for all your help!

For (a) I got 1.5e-10
For (b) I got 939 MeV
The answer for (c) is in GeV - not really sure what this means either.
 
Last edited:
Physics news on Phys.org
A gamma ray? Seems to be the only thing making sense in that context.
 
Hmmm... Okay, thanks. But I'm unclear about what to do with that information.
What if I do E=mc^2 with m being the combined mass of the proton and the antiproton (so really just 2 times the 1.67 etc.) and get that energy, does this get me anywhere? How do I connect that with gamma rays?
 
I don't know which educational level you are so I cannot really judge what's being asked of you. If "g ray" means gamma rays, then the question is either simplistic (to the point of being wrong) or a good deal more complicated than a) and b).

Simplistic version:
Gamma rays, more precisely the photons contained in a gamma ray, at very high energies can "spontaneously" transform into a particle anti-particle pair, usually an electron anti-electron pair (they actually do not do that spontaneously but only in the presence of a reaction partner, but that is exactly the complication I am ignoring here). This process is called pair production http://en.wikipedia.org/wiki/Pair_production" . The same way, a proton anti-proton pair could be produced by a gamma ray (photon). I do think that is the process that your question asks about. I find it a bit advanced to ask for pair production if you never heard about it.

More realistic version: In reality, the reaction partner has to be taken into account. You don't want details about that.

Final remark: Did I understand you correctly that you do not know what "GeV" is? That is giga-electronvolt: 1 GeV = 1000 MeV.
 
Last edited by a moderator:
Wow, thanks! That was really thorough and I understand the question now. Thanks for taking your time to help me! I truly appreciate it!
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 54 ·
2
Replies
54
Views
11K
Replies
20
Views
5K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K