Octets for Baryons: What is the Other Octet?

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In summary, the conversation is discussing the composition of quarks and hadrons and how they must follow certain statistical and symmetry rules. The octet in question is a representation of quark flavor, color, space, and spin, and the other octet refers to an excited state of the first octet with higher spin. The singlet is a combination of three spin-halfs and orbital angular momentum, and it is believed that the Λ(1890) particle fits this description.
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jono90one
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Hi,
I am just learning some materials and struggling to find what the other octet is. I know the following:
[itex]3 \otimes 3 \otimes 3 = 10 \oplus 8 \oplus 8 \oplus 1 [/itex]

Now I understand the 10 and one of the 8's. But I am a little unsure of what the other octet and singlet is in terms of quarks. Is the other octet just an excited state of the other octet (higher spin)??

http://proj.ncku.edu.tw/research/articles/e/20080523/images/080408014859tzxABW.gif
(This is the octet I already know)

Thanks.
 
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Quarks must obey Fermi-Driac statistics. Their wavefunction is a product of four parts: flavor, color, space and spin. All hadrons are colorless, meaning the color part is totally antisymmetric. In a ground state one assumes L = 0, meaning the space part is totally symmetric. This leaves flavor and spin, which together must be totally symmetric.

An SU(3) singlet is totally antisymmetric, meaning it wants to be combined with a totally antisymmetric spin part.

But three spin-halfs can only be combined in two ways: either as S = 3/2 (totally symmetric) or S = 1/2 (mixed). There is no totally antisymmetric way to combine three spin-halfs.

So the only remaining way to make a baryon which is an SU(3) singlet is to include orbital angular momentum. It's believed that the Λ(1890) is such a particle.
 

1. What are octets in terms of baryons?

Octets refer to a group of eight particles, specifically eight baryons, that are categorized based on their quark composition. These particles are divided into two groups: the baryon octet and the baryon decuplet.

2. What are the baryons in the other octet?

The baryon octet consists of eight particles: the proton, neutron, lambda, sigma, xi, and omega baryons. The "other octet" refers to the group of baryons that do not belong to the proton and neutron, which are the two most commonly known baryons. These particles include the lambda, sigma, xi, and omega baryons.

3. What is the significance of the other octet in particle physics?

The other octet is significant because it helps us understand the fundamental building blocks of matter. By studying the properties of these particles and how they interact with each other, we can gain a deeper understanding of the laws of nature and the structure of the universe.

4. How are the baryons in the other octet different from each other?

The baryons in the other octet have different masses and charges, which are determined by the number and type of quarks they are composed of. For example, the lambda baryon is composed of an up, down, and strange quark, while the sigma baryon is composed of two up quarks and one strange quark.

5. What is the role of the other octet in the Standard Model of particle physics?

The Standard Model is a theory that describes the fundamental particles and their interactions. The other octet is an essential part of this model, as it helps explain the behavior and properties of baryons, which are one of the building blocks of matter.

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