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shakeel
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what is R Parity and why?
R-parity is a symmetry often imposed in supersymmetric models.shakeel said:what is R Parity and why?
shakeel said:why there is a need for a new type of parity? is cpt voilated in supersymmetry
mormonator_rm said:R-parity is useful in the supersymmetric model of fundamental particles. You see, the standard fundamental particles, such as leptons, quarks, and the vector bosons all have positive R-parity, while the supersymmetric partners, such as sleptons, squarks, neutralinos and charginos have negative R-parity. This means that, in order to conserve the R-parity, only the following two-body decay transitions are allowed;
N --> NN
N --> SS
S --> NS
along with the following two-body scattering transitions;
NN --> NN
NN --> SS
SS --> SS
NS --> NS
where I have labeled "normal" (N) or standard fundamental particles and "supersymmetric" (S) fundamental particles. This means, for example, that a top quark could not decay into a charm quark and a neutralino, but a top quark could decay into a charm "squark" and a neutralino. Similarly, a "squark" cannot decay into another "squark" and a neutralino, but can decay into a quark and a neutralino. In all this, the standard decays which are well known in experimental physics remain allowed, such as quark transitions involving weak bosons. But it should be pointed out that a supersymmetric particle cannot decay into two new supersymmetric particles. All of these rules are a direct result of R-parity.
In order to prove the existence of R-parity, we now need to find some supersymmetric particles that exhibit these kinds of transitions. Experimentalists may be getting closer to this possibility, I hope.
nrqed said:Thank you for a very informative post! I have tried to understand the exact consequences of R parity by reading articles on SUSY but it has never been clear like that.
nrqed said:So a consequence of this is that the lightest SUSY particle is absolutely stable, even if it is much more massive than non-susy particles, right?
What is the lightest susy particle in MSSM?
R parity is a concept in particle physics that refers to a quantum number that determines the parity (odd or even) of a particle. It is used to distinguish between matter and anti-matter particles.
R parity is important because it helps explain the stability of matter in the universe. It ensures that the decay of certain particles is forbidden, which helps maintain the balance between matter and anti-matter.
R parity is measured by determining the parity of a particle and comparing it to the parity of its anti-particle. If they have opposite parities, the particle has R parity of +1, while if they have the same parity, the particle has R parity of -1.
Studying R parity can help us understand the fundamental laws of physics and the underlying principles of the universe. It has also been used to explain phenomena such as dark matter and neutrino oscillations.
R parity is a crucial factor in many current theories in particle physics, such as the Standard Model and Supersymmetry. It helps explain the behavior and interactions of particles and provides a framework for understanding the fundamental forces of the universe.