Non-central nature of nuclear force?

Click For Summary

Discussion Overview

The discussion revolves around the nature of nuclear forces, specifically their classification as non-central forces. Participants explore the implications of this classification on angular momentum, stability of the nucleus, and the role of electric quadrupole moments in indicating non-spherical structures within the nucleus.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants question how electric quadrupole moments indicate the non-spherical structure of the nucleus and its implications for stability when angular momentum is not constant.
  • One participant suggests that the shape of the charge distribution around the nucleus can be inferred from the sign of the electric quadrupole moment, indicating non-spherical structures like oblate or prolate ellipsoids.
  • A participant references classical Yukawa theory, arguing that it is clear the nuclear force is not a central potential.
  • Another participant discusses the Yukawa potential, acknowledging it as a central potential but suggesting that deviations occur in nuclear physics due to angular momentum state mixing, leading to the need for additional terms in models.
  • One participant mentions the role of "gamma5" in nucleon and pion interactions, noting its importance for parity conservation and spin-dependent interactions.

Areas of Agreement / Disagreement

Participants express differing views on the classification of the Yukawa potential and its implications for nuclear forces. There is no consensus on the nature of the nuclear force or the stability of the nucleus in relation to angular momentum.

Contextual Notes

Participants highlight the complexity of nuclear interactions and the need for phenomenological models to account for deviations from central potential behavior, indicating that assumptions about the nature of forces and angular momentum may vary.

Reshma
Messages
749
Reaction score
6
Nuclear forces are said to be non-central. By definition of central force, angular momentum is constant. It is usually found in spherical bodies. How do the electric quadruple moments indicate the non-spherical structure of the nucleus? How is the nucleus stable if the angular momentum is not constant?
 
Physics news on Phys.org
Hello? Can someone help me here?
 
Reshma said:
How do the electric quadruple moments indicate the non-spherical structure of the nucleus?
Based upon the sign of the electric quadrupolemoment, you know the shape of the charge distribution around the nucleus. It kind of expresses the electrical dipole you have because of a non-sferical structure (like oblate/prolate-ellipsoids)

Quadrupole moment

marlon
 
Take classical Yukawa theory, and expand it. Its pretty clear that its not a central potential.
 
Haelfix -- not for the usual scalar interation often used to explain the Yukawa potential. For nucleons and pions. The interaction includes "gamma5". Pions have negative parity, the gamma5 allows parity to be conserved, and provides a spin-dependent interaction.
Regards,
Reilly Atkinson
 
Yea I realized I misworded my response pretty badly.

The Yukawa potential *is* a central potential, but to see why the nuclear force is *not* it more or less suffices to look at the former and see where it must break down.

Qualitatively in Nuclear physics in many reactions you will get some small angular momentum state mixing that will depart from the Yukawa potential. Typically what is done is you add in these error terms and build a model around it by comparing to experiment. So for instance in pion exchange models you will get a central potential term like the Yukawa force (or Woods Saxon form) and something tensor like. From there its all phenomonology.
 

Similar threads

Graduate How does the strong force loses its strength with distance?
  • · Replies 3 ·
Replies
3
Views
4K
Undergrad Nuclear Force Behavior: Confusing Isospin Dependence
  • · Replies 11 ·
Replies
11
Views
3K
Undergrad Quadrupole deformation in nuclei
  • · Replies 9 ·
Replies
9
Views
2K
Undergrad How Does Beta Decay Relate to the Role of W Bosons in Weak Nuclear Force?
  • · Replies 4 ·
Replies
4
Views
5K
Graduate Does radioactive decay always result in a daughter nuclide in an excited state?
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Why 15 million K is sufficient for fusion in solar core?
  • · Replies 13 ·
Replies
13
Views
3K
How Are Wigner D Functions Related to Nuclear Rotor Model Wave Functions?
  • · Replies 2 ·
Replies
2
Views
2K
Graduate Regular vs stable orbits in spherically symmetric potentials
  • · Replies 4 ·
Replies
4
Views
1K
Undergrad Does Larmor precession change the force exerted on a magnetic dipole?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad W,Z,H and some fail in decoupling theorems
  • · Replies 1 ·
Replies
1
Views
1K