On-shell renormalization of the mixing matrices in Majorana neutrino theories
Abstract We generalize a recently proposed on-shell approach to renormalize the Cabibbo–Kobayashi–Maskawa quark-mixing matrix to the case of an extended leptonic sector that includes Dirac and Majorana neutrinos in the framework of the seesaw mechanism. An important property of this formulation is the gauge independence of both the renormalized and bare lepton mixing matrices. Also, the texture zero in the neutrino mass matrix is preserved.
On the On-Shell Renormalization of Fermion Masses, Fields, and Mixing Matrices at 1-loop
We propose a new and simple On-Shell definition of off-diagonal fermion field and mass counterterms at 1-loop in terms of self-energy scalar functions. Further, we show that the anti-hermitian part of the field renormalization is always finite and that mass counterterms can be chosen gaugeindependent. It is noteworthy that our definition relies on mass structures, which is a novel approach, and does not require to drop absorptive parts as is usually the case. Definitions of the off-diagonal mass and field counterterms allow us to comment on the renormalization of mixing matrices with focus on the quark mixing matrix in the Standard Model. As an example of our scheme, we provide computations in the Two Higgs Doublet Model with an additional Heavy Majorana neutrino — the Grimus-Neufeld model. This allows for the comparison with other schemes known in literature and also provides examples for the case of massless fermions. The examples also serve as genuine results in this particular model as well as this scheme.
New Low-Profile Applicators for Local Heating of Tissues
A new type of low-profile applicator is described giving efficient power transfer to tissue with low leakage. It consists of a resonant element spaced from a ground plane by low-loss material having high relative permittivity and some relative permeability. This combination is covered by similar material which can be placed in direct contact with the tissue to be heated, or separated from it by a water bolus as required. Laboratory measurements using phantom materials show that these applicators are well matched and produce well defined and relatively uniform heating profiles. Applicators having maximum dimensions of 3-15 cm covering the frequency range 1000-100 MHz, respectively, are described. Penetration depths of at least 4 cm at 100-200 MHz are achieved. Tests on anesthetised pigs and some clinical assessment have confirmed the usefulness of this compact low-frequency type of applicator and have shown that performance compares favorably with that of other recently reported types. The design can be optimized for treatment of specific sites, and suitable choice of dimensions and electrical characteristics of the layer material allow the low-profile concept to be extended over a wide range of operating frequencies.