Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userNon-decoupling of Heavy Neutrinos and Lepton Flavour Violation
119
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We consider a class of models predicting new heavy neutral fermionic states, whose mixing with the light neutrinos can be naturally significant and produce observable effects below the threshold for their production. We update the indirect limits on the flavour non-diagonal mixing parameters that can be derived from unitarity, and show that significant rates are in general expected for one-loop-induced rare processes due to the exchange of virtual heavy neutrinos, involving the violation of the muon and electron lepton numbers. In particular, the amplitudes for $mu$--$e$ conversion in nuclei and for $muto ee^+e^-$ show a non-decoupling quadratic dependence on the heavy neutrino mass $M$, while $muto egamma$ is almost independent of the heavy scale above the electroweak scale. These three processes are then used to set stringent constraints on the flavour-violating mixing angles. In all the cases considered, we point out explicitly that the non-decoupling behaviour is strictly related to the spontaneous breaking of the SU(2) symmetry.
rate research
Read More
We discuss lepton flavour violating processes induced in the production and decay of heavy right-handed neutrinos at the LHC. Such particles appear in left-right symmetrical extensions of the Standard Model as the messengers of neutrino mass generation, and can have masses at the TeV scale. We determine the expected sensitivity on the right-handed neutrino mixing matrix, as well as on the right-handed gauge boson and heavy neutrino masses. By comparing the sensitivity of the LHC with that of searches for low energy LFV processes, we identify favourable areas of the parameter space to explore the complementarity between LFV at low and high energies.
We did a model independent phenomenological study of baryogenesis via leptogenesis, neutrinoless double beta decay (NDBD) and charged lepton flavour violation (CLFV) in a generic left-right symmetric model (LRSM) where neutrino mass originates from the type I + type II seesaw mechanism. We studied the new physics contributions to NDBD coming from the left-right gauge boson mixing and the heavy neutrino contribution within the framework of LRSM. We have considered the mass of the RH gauge boson to be specifically 5 TeV, 10 TeV and 18 TeV and studied the effects of the new physics contributions on the effective mass and baryogenesis and compared with the current experimental limit. We tried to correlate the cosmological BAU from resonant leptogenesis with the low energy observables, notably, NDBD and LFV with a view to finding a common parameter space where they coexists.
If observed, charged lepton flavour violation is a clear sign of new physics - beyond the Standard Model minimally extended to accommodate neutrino oscillation data. We briefly review several extensions of the Standard Model which could potentially give rise to observable signals, also emphasising the r^ole of charged lepton flavour violation in probing such new physics models.
We study lepton flavour violating decays of neutralinos and sleptons within the Minimal Supersymmetric Standard Model, assuming two and three generation mixings in the slepton sector. We take into account the most recent bounds on flavour violating rare lepton decays. Taking the SPS1a scenario as an example, we show that some of the lepton flavour violating branching ratios of neutralinos and sleptons can be sizable (~ 5-10%). We study the impact of the lepton flavour violating neutralino and slepton decays on the di-lepton mass distributions measured at LHC. We find that they can result in novel and characteristic edge structures in the distributions. In particular, double-edge structures can appear in the e tau and mu tau mass spectra if ~tau_1 is the lightest slepton. The appearance of these remarkable structures provides a powerful test of supersymmetric lepton flavour violation at LHC.
It has been recently shown that the quantum Boltzmann equations may be relevant for the leptogenesis scenario. In particular, they lead to a time-dependent CP asymmetry which depends upon the previous dynamics of the system. This memory effect in the CP asymmetry is particularly important in resonant leptogenesis where the asymmetry is generated by the decays of nearly mass-degenerate right-handed neutrinos. We study the impact of the non-trivial time evolution of the CP asymmetry in the so-called Minimal Lepton Flavour Violation framework where the charged-lepton and the neutrino Yukawa couplings are the only irreducible sources of lepton-flavour symmetry breaking and resonant leptogenesis is achieved. We show that significant quantitative differences arise with respect to the case in which the time dependence of the CP asymmetry is neglected.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
