B Weak nuclear force - circumstances in which it is manifested

[arlesterc]

I have a glass of water at room temperature. The electromagnetic force is at play between the electrons and nucleus of the atoms, the strong nuclear force is at play holding the nucleus together, the force of gravity weak as it may be is at play between the various particles - electrons, quarks. Is the weak nuclear force at play as well? Are neutrons being converted into protons in this glass as is the case with the weak nuclear force be it in a very minimal way/not frequent but still happening? Or is the case that the weak nuclear force only manifests itself in special circumstances such as radioactive materials, extremely high temperature/high energy situations - sun, accelerators? From my reading it seems to only occur to free standing neutrons - not those bound in a nucleus - which I assume to be a special circumstance/special environmental situation - and which is not the case with my glass of water at room temperature. Thanks in advance for clarification on this point.

 

[mathman]

The weak nuclear force is involved in beta decay and similar processes (n to p or p to n inside nucleus). Water at room temperature will have beta decay only if there is tritium present, which decays to He3.

 

[arlesterc]

Thanks for the quick response. If tritium is present then somehow there ends up being unbound neutrons which decay into protons? I am asking because per this wiki note - https://en.wikipedia.org/wiki/Weak_interaction - "A particularly extreme example is the weak-force decay of a free neutron, which takes about 15 minutes." I thought the weak force only applied in the circumstances where there are free neutrons. Are you saying that bound neutrons - in the nucleus - an unstable nucleus - also have weak force decay? So in the nucleus of all radioactive elements the weak force is at work changing bound neutrons in the nucleus to protons? And the wiki example is not the general case that only free neutrons decay/exhibit the weak force?

 

[PeterDonis]

I thought the weak force only applied in the circumstances where there are free neutrons.

This is not the case. Beta decays of nuclei like tritrium are weak force decays.