R-parity

With an R-parity of -1 it is a possible candidate for dark matter.

As a consequence, in such theories R-parity remains exact at all energies.

The existence of a supersymmetric dark matter candidate is closely tied to R-parity.

R-parity is a concept in particle physics.

Another possibility is the gravitino, which only interacts via gravitational interactions and does not require strict R-parity.

He has made significant contributions to brane-world models of extra dimensions, quarkonium physics and R-parity violating supersymmetry.

In 2001 he presented his doctoral thesis titled Breaking of R-parity and supersymmetry in supersymmetric models.

Another solution is that R-parity is slightly violated and the gravitino is the lightest supersymmetric particle.

With R-parity being preserved, the lightest supersymmetric particle (LSP) cannot decay.

The crucial issue is to determine whether the sneutrino (the supersymmetric partner of neutrino), which is odd under R-parity, developes a vacuum expectation value.

This would be the case if the gravitino is the lightest supersymmetric particle particle and R-parity is conserved (or nearly so).

SUSY with R-parity, extra dimensions with KK-parity, and several other models fall into this category.

A very attractive way to motivate R-parity is with a B-L continuous gauge symmetry which is spontaneously broken at a scale inaccessible to current experiments.

Because proton decay involves violating both lepton and baryon number simultaneously, no single renormalizable R-parity violating coupling leads to proton decay.

R-parity is a symmetry acting on the Minimal Supersymmetric Standard Model (MSSM) fields that forbids these couplings and can be defined as:

After GUT symmetry breaking, this spinor parity descends into R-parity so long as no spinor fields were used to break the GUT symmetry.

This has motivated the study of R-parity violation where only one set of the R-parity violating couplings are non-zero which is sometimes called the single coupling dominance hypothesis.

With spin s, baryon number B, and lepton number L. All Standard Model particles have R-parity of 1 while supersymmetric particles have R-parity -1.

This natural occurrence of R-parity is possible because in SO(10) the Standard Model fermions arise from the 16-dimensional spinor representation, while the Higgs arises from a 10 dimensional vector representation.

In R-parity conserving models, the lightest neutralino is stable and all supersymmetric cascade-decays end up decaying into this particle which leaves the detector unseen and its existence can only be inferred by looking for unbalanced momentum in a detector.

In models in which R-parity is conserved and the lightest of the four neutralinos is the LSP, the lightest neutralino is stable and is eventually produced in the decay chain of all other superpartners.

R-parity Violating Supersymmetry by R.Barbier, C.Berat, M.Besancon, M.Chemtob, A.Deandrea, E.Dudas, P.Fayet, S.Lavignac, G.Moreau, E.Perez, and Y.Sirois.

If R-parity is preserved, then the lightest superparticle (LSP) of the MSSM is stable and is a Weakly interacting massive particle (WIMP) - i.e. it does not have electromagnetic or strong interactions.

R-parity sets all of the renormalizable baryon and lepton number violating couplings to zero and the proton is stable at the renormalizable level and the lifetime of the proton is increased to years and is nearly consistent with current observational data.

But R-parity prevents a direct decay to quarks and/or gluons, and on the other hand the only other colored supersymmetric particles are the squarks, that being bosons (spin 0, being the partners of the spin 1/2 quarks) have a much higher mass in Split SUSY.