Conservation of Bayron number, Lepton number and strangeness

In summary, the conversation discusses the various conservation laws in particle physics and cosmology, including energy, linear momentum, angular momentum, electric charge, and other fundamental properties such as baryon number, lepton number, and strangeness. These laws are based on the fundamental properties of matter, which have no explanation and "just are." The discussion also touches on the conservation of baryon number in particle decay, where it is shown that the combination of particles must have a total baryon number that is conserved. This conversation highlights the complexities of understanding the fundamental properties of nature in particle physics.
  • #1
Yael
18
0
Hi,

i'm stuck on my homework.. and this particle physics and cosmology chapter is killing me :yuck:

a question asks me to discuss the following conservation laws: energy, linear momentum, angular momentum, electric charge (ok so far) AND bayron number, lepton number and strangeness.
are all of these laws based on fundamental properties of nature? Explain.

Now i do get the laws of conservation of bayron, lepton and strangeness...
but what do they mean exactly by fundamental properties?

Thanks.
 
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  • #2
Fundamental properties of matter are those things that have no "why" beneath them. Mass is a property that matter has, so is charge. Turns out, as quantum was figured out, that there are more properties that just "are." "strangeness" is a property of matter. Its a strange property, hence its name. Don't worry about it now, it just "is."

Baryons and leptons are classifications for fundamental particles. There are many types of each, so "baryon-ness" is NOT a property. Energy and momentum are derived quantities.
 
  • #3
Excuse me for responding so far, but I think this can be helpful for somebody who visit this page.I´m going to talk about the baryon number. For example, in a neutron decay we can get a proton+electron+antineutrino; this transformation doesn´t violate the energy and charge conservation laws, and so we can set a question, why can't we obtain from this decay the combination electron+positron+one or more neutrinos and antineutrinos if that laws aren´t also broken?
The answer to this question was answered by Ernest Stückelberg (or something like that) that introduced heavy charges (now known as the bayron quantum number) who said that that number must be conservated as well in all the possible combinations of a decay and not into the forbidden ones, so neutron and proton are assumed to have the value of 1 for this number, electron, positron and neutrino are related to the 0 and the antiparticles to the additive inverse of the particle number.
So we get:
electron (0) +proton (1) + antineutrino (0)= 1 (neutron's bayron number), so this result is allowed.
electron (0) + positron (0) + neutrinos or antineutrinos (0)= 0 (the baryon number isn´t conserved and the result is forbidden)
I hope you find it useful. (For more information I reccomend see the book: facts and mysteries in elementary particle physics, written by Martinus Veltman)
 
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What is the Conservation of Bayron number?

The Conservation of Bayron number is a fundamental principle in particle physics that states the total Bayron number before and after a particle interaction must remain the same. This means that the number of Bayrons (a type of subatomic particle) before a reaction must equal the number of Bayrons after the reaction.

What is the Conservation of Lepton number?

The Conservation of Lepton number is a principle in particle physics that states the total lepton number in a system must remain constant. Leptons are a type of subatomic particle, such as electrons or neutrinos, and this principle ensures that the number of leptons before and after a reaction remains the same.

What is strangeness in particle physics?

Strangeness is a quantum number that describes the properties of subatomic particles, specifically hadrons (particles made up of quarks). It is related to the flavor of quarks and is conserved in all particle interactions.

Why is the conservation of Bayron number, lepton number, and strangeness important?

These conservation principles are important because they help us understand and predict particle interactions. They also provide evidence for the existence of subatomic particles and the fundamental laws of nature.

Can the conservation of Bayron number, lepton number, and strangeness be violated?

While these conservation laws hold true in the vast majority of particle interactions, there are a few rare cases where they can be violated. These violations are known as "flavor-changing" or "lepton-number-violating" processes and are still an area of active research in particle physics.

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