The lifetime of an unstable nucleus

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    Lifetime Nucleus
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Discussion Overview

The discussion revolves around the lifetime of unstable nuclei, particularly focusing on the interactions that govern their decay processes. Participants explore the differences between strong and weak interactions, as well as the mechanisms behind various types of radioactive decay, including beta, alpha, and gamma decays.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant notes the apparent contradiction between the strong force's rapid interactions and the long lifetimes of unstable nuclei, questioning how such long lifetimes are possible.
  • Another participant asserts that there is a confusion between weak decay and strong interactions, prompting further clarification on the forces involved in the decay of uranium.
  • A subsequent post emphasizes the need to understand the specific reactions that lead to decay, suggesting that this is key to addressing the initial question.
  • It is mentioned that beta decays are always weak due to the non-conservation of quark numbers, while alpha decays involve tunneling through a potential barrier, which can result in very small probabilities for decay. Gamma decays may also be long-lived depending on certain conditions related to dipole moments and photon emissions.
  • Another participant points out that the electromagnetic interaction is weaker than the strong interaction, which may influence decay processes.

Areas of Agreement / Disagreement

Participants express differing views on the interactions responsible for nuclear decay, particularly regarding the roles of weak and strong forces. The discussion remains unresolved with multiple competing perspectives on the mechanisms of decay.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the interactions and the specific conditions under which different decay processes occur. The dependence on definitions of decay types and the mathematical treatment of tunneling probabilities are also noted but not resolved.

wdlang
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protons and neutrons interact with each other with the strong force, which is very strong

however, there are many unstable nucleus which have a lifetime in the order of millions of years

this is quite strange

the time scale of strong interaction is many many orders smaller than that of the lifetime

how is this possible?
 
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you are confusing weak decay with strong interactions.
 
andrien said:
you are confusing weak decay with strong interactions.

what is the force responsible for the decay of Ur?

weak interaction or strong interaction?
 
By what reaction it decay.that is the answer.
 
Beta decays are always weak (quark numbers are not conserved).
Alpha decays have a different issue: Those alpha particles do not have enough energy to escape in a classical way - they have to tunnel through a potential barrier, and the tunneling probability can be very small.
Gamma decays can be long-living, if they do not have a (significant) dipole moment, and require the emission of multiple photons at the same time. And, of course, the electromagnetic interaction is weaker than the strong interaction.
 

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