Weak dipole moments of the tau lepton in models with an extended scalar sector

Abstract

We consider renormalizable couplings of neutral $\varphi$, singly ${\varphi }^{\pm }$, and doubly charged ${\varphi }^{\pm \pm }$ scalar bosons to leptons and the $Z$ gauge boson and calculate the one-loop contributions to the anomalous weak magnetic dipole moment (AWMDM) $a_{\tau }^W$ and the weak electric dipole moment (WEDM) $d_{\tau }^W$ of a charged lepton in a model independent way. The analytic expressions are presented in terms of both parametric integrals and Passarino-Veltman scalar functions. Among the new contributions, there are those arising from the vertices of the type ${\varphi }^{\pm }{W}^{\mp }Z$ and $Z{\varphi }_i{\varphi }_j$ ($i\ne j$), along with contributions from doubly charged scalar bosons. Both $a_{\tau }$ and $d_{\tau }^W$ are evaluated in several scenarios , first in a model independent way and then within some popular models, such as two-Higgs doublet models (THDMs), multiple-Higgs doublet models and Higgs triplet models. As far as $a_{\tau }^W$ is concerned, its real part reaches values as high as $10^{-10}-10^{-9}$ for masses of the new scalar bosons in the 200 GeV range, whereas the imaginary part is one or two orders of magnitude below. On the other hand, the most promising scenario for a nonvanishing WEDM is offered by a $CP$-violating THDM in a scenario where the heavy neutral scalar bosons are a mixture of $CP$ eigenstates. It is found that the real part of $d_{\tau }^W$ is of the order of $10^{-24}$ ecm and its imaginary part can reach the $10^{-26}$ ecm level for masses of the new scalar bosons of the order of a few hundred of GeVs. Both the tau AWMDM and WEDM decrease dramatically as the scalar boson masses increase.

26 pages, 13 figures

References in corpus (10)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• Neutrino Masses and the LHC: Testing Type II Seesaw
• Building and testing models with extended Higgs sectors
• Symmetry breaking patterns in 3HDM
• Indirect constraints on the Georgi-Machacek model and implications for Higgs couplings
• Discrete symmetries in the three-Higgs-doublet model
• Novel Constraint on Parameter Space of the Georgi-Machacek Model by Current LHC Data
• Surveying the Scope of the SU(2)_L Scalar Septet Sector
• Weak properties of the tau lepton via a spin-0 unparticle

Cited by in corpus (3)

• A new evaluation of the $HZZ$ coupling: direct bounds on anomalous contributions and $CP$ violating effects via a new asymmetry
• Weak dipole moments of heavy fermions with flavor violation induced by $Z^{\prime }$ gauge bosons
• Lessons from LHC on the LFV Higgs decays $h\to {\ell }_a{\ell }_b$ in the Two-Higgs Doublet Models