Compare & contrast properties of strong & weak interactions

In summary, the strong and weak interactions have different properties and strengths. The strong interaction involves only quarks and is mediated by gluons, which are massless and lead to a long-range force. It can also involve hadrons, not just bare quarks. On the other hand, the weak interaction can involve all leptons and quarks and is mediated by W± or Z bosons. However, it falls off with distance and can violate conservation laws. The relative strengths of the interactions are due to the mass and range of the particles that mediate them. The gluons, being massless, lead to a long-range force, while the W & Z bosons, being very massive, have a short range.
  • #1
Flucky
95
1
Hi all - in the question below I could do with some help on the "..explanation for the relative strengths..." bit, as I can't think of anything to say.

1. Homework Statement

Compare and contrast the properties of the strong and weak interactions. Include in your account an explanation for the relative strengths of the interactions, the types of particles affected by each interaction and other distinguising characteristics.

Homework Equations


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The Attempt at a Solution


Weak interactions can involve all leptons and quarks, and are mediated by W± or Z bosons; whereas strong interactions can only involve quarks (binding them as hadrons) and are mediated by gluons. The strength of the weak interaction falls of with distance (~10-2 at 10-18 m to ~10-13 at 10-15 m) which is opposite for the case of the strong interaction (~1 at large distances to <1 at small distances). Weak interactions can also violate conservation laws such as parity, strangeness and isospin - which the strong interaction cannot.

The question is worth 4 marks (which I know doesn't mean much out of context) so I think I would need to cover the main aspects of each. As I said above I am not sure what to put for the explanation for the relative strengths.


Cheers.
 
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  • #2
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  • #3
For those who might read this in future, my lecturer came back to me with a few things more that should be said:

Gluons are massless, leading to a long-range force. They couple to colour (carried by quarks) and also carry composite colour, so can interact with each other, which leads to colour-screening effects at short distance. The strength of the force therefore increases with increasing distance (or decreasing momentum transfer).
(The strong interaction can involve hadrons - particles made of quarks - not just the bare quarks themselves.)
The W & Z are very massive (80-90 GeV/c^2), leading to a very short range. (You do give the fall with distance.) At very short distances (10^-18 m), the strength is no less than the EM interaction.
 

1. What are strong and weak interactions?

Strong and weak interactions are two types of fundamental forces that govern interactions between subatomic particles. Strong interactions are responsible for holding the nucleus of an atom together, while weak interactions are involved in processes such as radioactive decay.

2. How do strong and weak interactions differ?

Strong interactions are much stronger than weak interactions, with a strength about 100 times greater. Strong interactions also have a shorter range than weak interactions, acting only within the nucleus of an atom, while weak interactions can act over larger distances.

3. What are some examples of strong and weak interactions?

Strong interactions are responsible for binding protons and neutrons together in the nucleus of an atom, as well as the interactions between quarks, which make up protons and neutrons. Weak interactions are involved in processes such as beta decay, where a neutron turns into a proton and emits an electron and an antineutrino.

4. How are strong and weak interactions related to the other fundamental forces?

Strong and weak interactions are two of the four fundamental forces, along with electromagnetism and gravity. While electromagnetism and gravity have infinite range, strong and weak interactions are only effective at the subatomic level.

5. What are the implications of understanding strong and weak interactions?

Understanding strong and weak interactions is crucial for understanding the behavior of matter at the smallest scales. It has allowed scientists to develop models and theories that explain the structure of the atomic nucleus and the behavior of subatomic particles, leading to advancements in fields such as particle physics and nuclear energy.

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