Why is the strength of weak nuclear force important ?

In summary: This is due to the fact that neutrons are slightly heavier than protons, so they are more likely to decay into protons. However, the overall balance of particles in the universe is still maintained due to other processes, such as fusion in stars, which can create heavier elements from lighter ones. This helps to explain the relationship between the mass of particles and their present numbers in the universe.
  • #1
thatoekhant
15
0
I am just a student. I read that if the strength of weak nuclear force were stronger than current value, this would cause the rarity of neutrons. And, if the strength of weak nuclear force were weaker than current value, this would cause most of hydrogen to convert to helium. I can't understand those statement. Why ? Please !

Thanks in advance.
 
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  • #2
Well, the weak force is responsible for the beta decays. Thus, a larger coupling constant would result in reduced lifetimes of the decaying particles - e.g. the neutron.
The beta decay also plays a role in the fusion process H + H -> He.
In the 1st step, a deuterium nucleus will be formed
p + p -> p + n + positron + neutrino
So, a beta+ decay of the proton is involved. A higher coupling constant would increase the fusion H + H -> He
 
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  • #3
Thanks. But, some say that if there were rarity of neutrons, number of helium atom would be rare during big bang. But, I think even if there had not been sufficient heliums and only hydrogen atoms exists, formed stars would have converted hydrogens to helium by changing a proton to a neutron so helium will not be rare anyway. That will make the production of heavier elements without problems cos there are helium atoms produced by stars by converting hydrogens to helium. So, I think rarity of helium atom during big bang is not a problem. Is that right ? Please !
Thanks in advance.
 
  • #4
The fact that the weak nuclear force is at a critical point of balance is significant. The events of the big bang (if there was such a thing) would not affect things so much as an ongoing effect of shorter particle lifetimes or reduced stability in atoms. The values of various forces hold atoms in a balanced way. The strong and weak nuclear forces and electromagnetic forces set up repulsive/attractive fields which locate each particle within a certain zone of an atom or molecule. Our understanding of it depends upon careful study of what we can measure of nanoscopic interactions. I think a little knowledge is a bad thing. How can you propose that it wouldn't matter if the weak nuclear force were different? And please rather than "some say" grab a reference. Tell us who says it, that really helps to explain what you mean.
 
  • #5
Thanks a lot. I would like to ask some questions. If there were no weak nuclear force, the sun would not burn because there would be no deuterium . And, di protons are extremely unstable. So, The sun would not burn . Is that right ? Besides, may I know the life time of a di proton , please. And also, May I know whether the mass of the formed diproton is less than the two H1 hydrogen atoms or not . Does a proton decay to a neutron every 10 minutes in the sun ?
Thanks in advance!
 
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  • #6
If there would be no weak force, the big bang would have happened completely different. So different that I have no idea how our universe would look like.

Assuming the weak force would have "vanished" in some way after the big bang: neutrons would be stable and fuse with protons quickly, so deuterium would not be an issue. Could shorten the lifetime of stars, as deuterium fusion is way quicker than the proton-proton reaction.

Diprotons are so short-living, the decay process has to happen "nearly at the same time".

Does a proton decay to a neutron every 10 minutes in the sun ?
I don't think that question makes sense.
 
  • #7
I would like to ask a question . As far as I know , number of protons is greater than that of neutrons in the universe. I have read that it is because the mass of neutron is slightly greater than that of proton. Could someone explain me relationship between mass of particles and their present numbers ?
Thanks in advance!
 
  • #8
A particle cannot decay to a heavier particle - that would need additional energy from somewhere.
It is possible that a particle can decay to lighter particles - not all processes are possible, but neutrons can decay to protons.

As a result, the universe has more protons than neutrons.
 

What is the weak nuclear force?

The weak nuclear force is one of the four fundamental forces in nature, along with gravity, electromagnetism, and the strong nuclear force. It is responsible for the decay of subatomic particles and plays a crucial role in the stability of atoms.

Why is understanding the weak nuclear force important?

Understanding the weak nuclear force is important because it helps us to understand the behavior of subatomic particles and their interactions. It also allows us to explain processes such as radioactive decay and nuclear fusion.

How does the weak nuclear force differ from the other fundamental forces?

The weak nuclear force is unique in that it only acts over very short distances, and its strength is much weaker than the other three forces. It also primarily affects particles that have a property called "spin."

What are the practical applications of the weak nuclear force?

While the weak nuclear force may seem abstract, it has many practical applications. For example, in nuclear power plants, it is used to harness energy from nuclear reactions. It also plays a role in medical imaging techniques such as PET scans.

How does the strength of the weak nuclear force impact the universe?

The weak nuclear force is crucial for the formation of elements and the stability of stars. Without it, the universe as we know it would not exist. It also plays a role in the evolution of the universe and the creation of heavy elements through processes such as stellar nucleosynthesis.

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