arXiv subjects

G. Barenboim

Publications and source records attributed to G. Barenboim.

93 records · Page 6Linked to original sources

arXiv1996

Spontaneous breakdown of CP in left-right symmetric models

We show that it is possible to obtain spontaneous CP violation in the minimal $SU(2)_L \times SU(2)_R \times U(1)_{B-L}$, i.e. in a left right symmetric model containing a bidoublet and two triplets in the scalar sector. For this to be a natural scenario, the non-diagonal quartic couplings between the two scalar triplets and the bidoublet play a fundamental role. We analyze the corresponding Higgs spectrum, the suppression of FCNC's and the manifestation of the spontaneous CP phase in the electric dipole moment of the electron.

hep-ph↗

arXiv1995

Relativistic Two-Body Processes in Axial-Charge Transitions

We study the contribution of two-body meson-exchange processes to axial charge transitions for nuclei in the lead, tin and oxygen regions. We conduct calculations in the Dirac-Hartree (the Walecka model) and the relativistic Hartree (where the full one-nucleon-loop effects are included) approximations. We present results indicating that one- and two-body processes enhance the matrix elements of the axial-charge operator by some (100+-20)% in all three regions studied. This agrees well with the fit of eighteen first-forbidden beta-decay transitions conducted by Warburton in the lead region. We also discuss some sensitivities present in the calculation.

nucl-th↗

arXiv1995

Non-decoupling of Heavy Neutrinos and Lepton Flavour Violation

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 $μ$--$e$ conversion in nuclei and for $μ\to ee^+e^-$ show a non-decoupling quadratic dependence on the heavy neutrino mass $M$, while $μ\to eγ$ 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.

hep-ph↗