Search results for "Formulation"
showing 10 items of 265 documents
The Minimal Flavour Violation benchmark in view of the latest LHCb data
2012
We derive the consequences of the MFV hypothesis for $\Delta F =1$ flavour observables based on the latest LHCb data. Any future measurements beyond the MFV bounds and relations unambiguously indicate the existence of new flavour structures next to the Yukawa couplings of the Standard Model.
Masses, mixings, Yukawa couplings and their symmetries
1993
We present a method to find the number of real and imaginary observable parameters coming from the Yukawa sector in an arbitrary gauge theory. The method leads naturally to a classification of Yukawa couplings according to their symmetries and suggests a new parametrization of masses and mixings that is useful to study the behaviour of Yukawa couplings under the renormalization group. We apply it to some examples based on the Standard Model with Yukawa couplings obeying various chiral symmetries. We also show how our method of parameter counting can be used in some models with an enlarged leptonic sector.
Electric dipole moments from flavoredCPviolation in supersymmetry
2008
The so-called supersymmetric flavor and $CP$ problems are deeply related to the origin of flavor and hence to the origin of the standard model Yukawa couplings themselves. We show that realistic $SU(3)$ flavor symmetries with spontaneous $CP$ violation reproducing correctly the standard model Yukawa matrices can simultaneously solve both problems without ad hoc modifications of the supersymmetric model. We analyze the leptonic electric dipole moments and lepton flavor violation processes in these models. We show that the electron electric dipole moment and the decay $\ensuremath{\mu}\ensuremath{\rightarrow}e\ensuremath{\gamma}$ are naturally within reach of the proposed experiments if the s…
The two-loop supersymmetric corrections to lepton anomalous magnetic and electric dipole moments
2006
Using the effective Lagrangian method, we analyze the electroweak corrections to the anomalous dipole moments of lepton from some special two-loop topological diagrams which are composed of neutralino (chargino) - slepton (sneutrino) in the minimal supersymmetric extension of the standard model (MSSM). Considering the translational invariance of the inner loop momenta and the electromagnetic gauge invariance, we get all dimension 6 operators and derive their coefficients. After applying equations of motion to the external leptons, the anomalous dipole moments of lepton are obtained. The numerical results imply that there is a parameter space where the two-loop supersymmetric corrections to …
CP violating lepton asymmetries in left-right models
1998
Lepton charge asymmetries can be used as an alternative means of searching for new physics. They are interesting because they are small in the Standard Model and therefore, necessarily evidence new physics. In this work we explore the use of lepton asymmetries as a probe of the flavour structure of the left-right symmetric model with spontaneous CP violation. We find that new physics may enhance the magnitude of $a_{SL}$ up to the precent level within the appropiate parameter space.
Leptonic Generation Mixing, Noncommutative Geometry and Solar Neutrino Fluxes
1997
Triangular mass matrices for neutrinos and their charged partners contain full information on neutrino mixing in a most concise form. Although the scheme is general and model independent, triangular matrices are typical for reducible but indecomposable representations of graded Lie algebras which, in turn, are characteristic for the standard model in noncommutative geometry. The mixing matrix responsible for neutrino oscillations is worked out analytically for two and three lepton families. The example of two families fixes the mixing angle to just about what is required by the Mikheyev-Smirnov-Wolfenstein resonance oscillation of solar neutrinos. In the case of three families we classify a…
One-loop effective lagrangian for an extension of the standard model with a heavy charged scalar singlet
1994
We study several problems related to the construction and the use of effective Lagrangians by considering an extension of the standard model that includes a heavy scalar singlet coupled to the leptonic doublet. Starting from the full renormalizable model, we build an effective field theory by integrating out the heavy scalar. A local effective Lagrangian (up to operators of dimension six) is obtained by expanding the one-loop effective action in inverse powers of the heavy mass. This is done by matching some Green functions calculated with both the full and the effective theories. Using this simple example we study the renormalization of effective Lagrangians in general and discuss how they…
Invariants and flavour in the general Two Higgs Doublet Model
2012
The flavour structure of the general Two Higgs Doublet Model (2HDM) is analysed and a detailed study of the parameter space is presented, showing that flavour mixing in the 2HDM can be parametrized by various unitary matrices which arise from the misalignment in flavour space between pairs of various Hermitian flavour matrices which can be constructed within the model. This is entirely analogous to the generation of the CKM matrix in the Standard Model (SM). We construct weak basis invariants which can give insight into the physical implications of any flavour model, written in an arbitrary weak basis (WB) in the context of 2HDM. We apply this technique to two special cases, models with MFV…
QUANTUM YANG-MILLS THEORY ON ARBITRARY SURFACES
1992
We study quantum Maxwell and Yang-Mills theory on orientable two-dimensional surfaces with an arbitrary number of handles and boundaries. Using path integral methods we derive general and explicit expressions for the partition function and expectation values of contractible and noncontractible Wilson loops on closed surfaces of any genus, as well as for the kernels on manifolds with handles and boundaries. In the Abelian case we also compute correlation functions of intersecting and self-intersecting loops on closed surfaces, and discuss the role of large gauge transformations and topologically nontrivial bundles.
Leptogenesis with conservation of B–L
2012
Abstract We study leptogenesis in the decay of heavy Standard Model singlet fermions which carry lepton number, in a framework without Majorana masses above the electroweak scale. Based on M. C. Gonzalez-Garcia, J. Racker, N. Rius, JHEP 11 (2009) 079.