46 research outputs found
Triangular mass matrices of quarks and Cabibbo-Kobayashi-Maskawa mixing
Every nonsingular fermion mass matrix, by an appropriate unitary
transformation of right-chiral fields, is equivalent to a triangular matrix.
Using the freedom in choosing bases of right-chiral fields in the minimal
standard model, reduction to triangular form reduces the well-known ambiguities
in reconstructing a mass matrix to trivial phase redefinitions. Furthermore,
diagonalization of the quark mass sectors can be shifted to one charge sector
only, without loosing the concise and economic triangular form. The
corresponding effective triangular mass matrix is reconstructed, up to trivial
phases, from the moduli of the CKM matrix elements, and vice versa, in a unique
way. A new formula for the parametrization independent CP-measure in terms of
observables is derived and discussed.Comment: 13 pages, Late
Gauge dependence and renormalization of in the MSSM
Well-known and newly developed renormalization schemes for are
analyzed in view of three desirable properties: gauge independence, process
independence, and numerical stability in perturbation theory. Arguments are
provided that no scheme can meet all three requirements, and as an
illustration, a ``No-Go-Theorem'' for the renormalization of is
established. Nevertheless, two particularly attractive schemes emerge. A
discussion about which scheme might be the best compromise in practice is
given.Comment: 20 pages, improved version that was published in PRD D66 (2002