The Mysterious Nature of Neutrons: Stability & Binding

Click For Summary

Discussion Overview

The discussion centers on the nature of neutrons, particularly their role in binding with protons and their stability outside of the nucleus. Participants explore why neutrons do not bind with each other and the implications of neutron decay and stability.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions why neutrons do not bind with other neutrons, suggesting a relationship to their instability outside the nucleus.
  • Another participant states that identical fermions do not bind, referencing a related thread for further context.
  • A different participant provides specific mass and lifetime values for neutrons and protons, discussing the energetics of neutron decay in the context of the deuteron and asserting that neutron decay is not energetically possible in stable nuclei.
  • One participant describes the nucleus as being held together by pion exchange, comparing it to Van der Waals forces in molecular interactions, while expressing uncertainty about the accuracy of this analogy.

Areas of Agreement / Disagreement

Participants present multiple competing views regarding the binding nature of neutrons and the mechanisms involved in nuclear stability, with no consensus reached on the underlying reasons for these phenomena.

Contextual Notes

Some claims depend on specific definitions of binding and stability, and there are unresolved questions regarding the energetics of neutron decay and the interactions within the nucleus.

textbooks
Messages
14
Reaction score
0
Neutrons bind Protons in nuclei, and/or the other way around, but why don't

Neutrons bind Neutrons, with clumps of neutrons whizzing about?

And, I'm guessing this is related: Why is a Neutron unstable outside

its nucleus with about a 10.3 minute half-life?
 
Physics news on Phys.org
If we consider the neutron alone, it has a mass of 939.565330 MeV/c2, and a lifetime of 885.7 seconds. The proton mass is 938.271998 MeV/c2, so the difference is 1.2933 MeV/c2. But the binding energy of the deuteron is about 2.2 MeV, and the only possible final state of neutron decay in the deuteron is two free protons plus an electron (+ neutrino). because the electron mass is 0.511 MeV/c2, neutron decay in the deuteron is energetically not possible. This true for all neutrons in all stable nuclei.
 
The nucleus is a bag of nucleons (neutrons and protons) held together by pion exchange. The process is analogous to how Van de Waals forces can hold molecules together.

(Every time I try to write something like this I cringe a little at how wrong it is...)
 

Similar threads

  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 3 ·
Replies
3
Views
4K
Replies
11
Views
2K
  • · Replies 12 ·
Replies
12
Views
5K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 1 ·
Replies
1
Views
3K