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arroy_0205
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Graviton is a spin 2 particle. Why is its superpartner gravitino a spin 3/2 (2-1/2) particle and not a spin 5/2 (2+1/2) particle?
Well we can ask the same question about fermions (1/2-1/2 and not 1/2+1/2) or electroweak gauge bosons..Graviton is a spin 2 particle. Why is its superpartner gravitino a spin 3/2 (2-1/2) particle and not a spin 5/2 (2+1/2) particle?
Atakor said:Well we can ask the same question about fermions (1/2-1/2 and not 1/2+1/2) or electroweak gauge bosons..
the point is that it is "simpler" to construct supermultiplets with particles and sparticles that respect this scheme (s-1/2 and not s+1/2).
Think about the Chiral supermultiplet. we have a fermion with two degrees of freedom, so the simplest bosonic thing to add is a complex scalar field..
The spin of a particle is a fundamental property that describes its angular momentum. In the case of the gravitino, it has a spin of 3/2 because it is a fermion, which means it follows the fermionic statistics and has a half-integer spin value. This is determined by the spin-statistics theorem, which states that all particles with half-integer spin are fermions.
The spin of a particle plays a crucial role in its interactions with other particles. In the case of the gravitino, its spin of 3/2 makes it a spin-3/2 fermion, which means it interacts through the gravitational force with other particles. This is because the gravitino is the supersymmetric partner of the graviton, the carrier particle of the gravitational force.
According to the laws of quantum mechanics, the spin of a particle is a conserved quantity and cannot change. Therefore, the gravitino will always have a spin of 3/2 in any interaction or physical process.
The spin of the gravitino was first predicted by theoretical models in the 1970s, which proposed the existence of supersymmetry. Later on, experiments at particle accelerators, such as the Large Hadron Collider, confirmed the existence of supersymmetric particles, including the gravitino, and their predicted spin values.
Yes, the gravitino is not the only particle with a spin of 3/2. Other examples include the Delta baryon and the Omega baryon, which are both hadrons made up of three quarks. However, the gravitino is unique in that it is the only spin-3/2 fermion that interacts through the gravitational force.