Regarding electron-positron annihilation

  • Context: High School 
  • Thread starter Thread starter Rev. Cheeseman
  • Start date Start date
  • Tags Tags
    annihilation
Click For Summary

Discussion Overview

The discussion revolves around the process of electron-positron annihilation and the fate of the resulting photons. It explores the theoretical implications and conceptual understanding of particle interactions and photon behavior following annihilation events.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant states that when an electron and a positron collide, they become photons, questioning where the photons go afterward.
  • Another participant suggests that the photons propagate outward from the annihilation point at the speed of light, noting that their absorption depends on what they encounter.
  • A later reply mentions that high-energy photons can produce new electron-positron pairs, illustrating this with a bubble-chamber example.
  • There is a reiteration of the uncertainty regarding whether the photons are absorbed or simply disappear, comparing it to photons emitted from a light bulb or star.

Areas of Agreement / Disagreement

Participants express differing views on the fate of the photons, with some suggesting they propagate outward while others emphasize the uncertainty of their absorption or disappearance. No consensus is reached on the definitive outcome of the photons post-annihilation.

Contextual Notes

The discussion does not resolve the assumptions regarding the conditions under which photons may be absorbed or the specific scenarios of their propagation.

Rev. Cheeseman
Messages
360
Reaction score
21
When an electron meets an anti-electron which is also known as positron and collide, the particles will become photons. But where did the photons go after the electron-positron annihilation happened?
 
Physics news on Phys.org
Outward.
 
Vanadium 50 said:
Outward.
I mean do they ended up absorbed by something or simply gone?
 
They simply propagate out away from the point of annihilation at the speed of light. Whether they get absorbed depends on what they encounter along the way. It's similar to what happens to the photons that leave your flashlight.
 
If the photons have high enough energy, they can in turn produce new electron-positron pairs. This bubble-chamber picture shows a positron (orange) entering from the lower left and annihilating with an electron in the bubble-chamber fluid. One of the photons (purple-dot path) produces an electron-positron pair (green) at upper right. The other photon (invisible) leaves the field of view.

k2epl1.jpg


(Source at CERN)
 
Reply
  • Like
Likes   Reactions: PeroK
wonderingchicken said:
I mean do they ended up absorbed by something or simply gone?
Depends on what they hit. Just like photons from a light bulb or a star.
 

Similar threads

Undergrad How Do Positrons Reach Cloud Chambers Without Annihilating?
  • · Replies 5 ·
Replies
5
Views
3K
High School Particle creation and annihilation
  • · Replies 2 ·
Replies
2
Views
1K
Undergrad Positron discovery in cloud chamber, how so?
  • · Replies 3 ·
Replies
3
Views
3K
High School Beta Plus Decay: What's Left for the Electron?
  • · Replies 8 ·
Replies
8
Views
3K
High School Can a hypothetical atom be made out of positrons and electrons ?
  • · Replies 9 ·
Replies
9
Views
3K
High School Anti-matter and matter annihilation
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad How often would a ϕ meson decay to a electron-positron pair?
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Why KE of Annihilation Electrons Differs?
  • · Replies 11 ·
Replies
11
Views
2K
High School But WHY do antimatter and matter annihilate on contact?
  • · Replies 1 ·
Replies
1
Views
13K
High School What does QFT really predict about matter/anti-matter interactions?
  • · Replies 6 ·
Replies
6
Views
2K