Neutron Isomerie: Can Neutronium Have Metastable Stage?

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Discussion Overview

The discussion centers around the concept of neutron isomerism and the possibility of neutronium existing in a metastable state. Participants explore whether hadrons can be in excited states and the implications for half-lives of nuclear isomers, particularly in relation to neutrons.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that hadrons can exist in excited states, which may be classified as separate hadrons based on their internal configurations.
  • Others argue that excited states generally have shorter half-lives compared to ground states, raising questions about the stability of neutronium in a metastable state.
  • A participant points out that certain isomers, like Sodium-22m, can have longer half-lives than expected, although this does not necessarily mean they are more stable than the ground state.
  • Another participant mentions that while there are nuclear isomers with longer half-lives, single hadrons typically do not exhibit such metastability, decaying within very short timeframes.
  • One participant provides examples of drastic changes in half-lives due to selection rules and the Pauli effect, illustrating the complexity of decay processes in different contexts.

Areas of Agreement / Disagreement

Participants express differing views on the stability and half-lives of excited states and isomers, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

The discussion highlights limitations in understanding the conditions under which neutronium might exhibit metastability and the specific definitions of stability and half-life in various contexts.

Garlic
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Hello everyone,
Can a hadron be in an excited stage? If yes, can neutrons -the element- neutronium have a nuclear isomer in a metastable stage, making it have a longer half life?
 
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Garlic said:
Can a hadron be in an excited stage?
Yes, but hadrons with the same quark content but different internal configuration will generally be listed as separate hadrons.

Garlic said:
If yes, can neutrons -the element- neutronium have a nuclear isomer in a metastable stage, making it have a longer half life?
Excited states generally have shorter half-lives than the ground states.
 
[QUOTE="Excited states generally have shorter half-lives than the ground states.[/QUOTE]

I understand, but aren't some Isomers of an Atom (Sodium-22m for example) have longer half live, and the letter "m" is put in order to indicate that it is an Isomer with a higher half life?
 
The m means that it is more stable than you would typically expect. It does not mean that it is more stable than the ground state. For example sodium 22 has a half life 2.6 years while sodium 22m has a half life of roughly 250 ns.
 
Orodruin said:
The m means that it is more stable than you would typically expect. It does not mean that it is more stable than the ground state. For example sodium 22 has a half life 2.6 years while sodium 22m has a half life of roughly 250 ns.

Okay. Thank you..
 
There are nuclear isomers with a longer half-life - most notably 180mTa where no decay has been observed so far (half-life > 1015 years) while the ground-state has a half-life of just 8 hours.

Single hadrons don't show such metastability. If they can decay via the strong or electromagnetic interaction they do so within ~10-20 seconds. If they can decay via the weak interaction only they live longer, but apart from the neutron "longer" still means pico- to nanoseconds.
 
Here's the explanation for this astonishing phenomenon. It's a drastic example for the application of selection rules:

http://en.wikipedia.org/wiki/Nuclear_isomer#High_spin_suppression_of_decay

Another drastic change in halflife of a beta-decaying nucleus can be due to the Pauli effect, the socalled bound-state beta decay. A nice example is Re187. This isotope as a neutral atom has a half-life of about ##40 \cdot 10^{9} yr##. As measured in the storage ring at the heavy-ion research center in Darmstadt (GSI), the half-life of a Re187 ion is only about 33 yr! The reason is that the beta-decay electron cannot be emitted easily in the case of the atom with all its electrons around, because it's energy is such that it would have to end up in an occupied atomic state.

That's pretty important in astrophysics, as you can read here:

http://www.euroschoolonexoticbeams.be/site/files/nlp/LNP651_contrib5.pdf
 
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