Magnetic moments of leptons, charged lepton flavor violations and dark matter phenomenology of a minimal radiative Dirac neutrino mass model
Bibhabasu De, Debottam Das, Manimala Mitra, Nirakar Sahoo
Abstract
A bstract In a simple extension of the standard model (SM), a pair of vector like lepton doublets ( L 1 and L 2 ) and a SU(2) L scalar doublet ( η ) have been introduced to help in accommodating the discrepancy in determination of the anomalous magnetic moments of the light leptons, namely, e and μ . Moreover, to make our scenario friendly to a Dirac like neutrino and also for a consistent dark matter phenomenology, we specifically add a singlet scalar ( S ) and a singlet fermion ( ψ ) in the set-up. However, the singlet states also induce a meaningful contribution in other charged lepton processes. A discrete symmetry $$ {\mathcal{Z}}_2\times {\mathcal{Z}}_2^{\prime } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>Z</mml:mi> <mml:mn>2</mml:mn> </mml:msub> <mml:mo>×</mml:mo> <mml:msubsup> <mml:mi>Z</mml:mi> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msubsup> </mml:math> has been imposed under which all the SM particles are even while the new particles may be assumed to have odd charges. In a bottom-up approach, with a minimal particle content, we systematically explore the available parameter space in terms of couplings and masses of the new particles. Here a number of observables associated with the SM leptons have been considered, e.g., masses and mixings of neutrinos, ( g − 2) anomalies of e , μ , charged lepton flavor violating (cLFV) observables and the dark matter (DM) phenomenology of a singlet-doublet dark matter. Neutrinos, promoted as the Dirac type states, acquire mass at one loop level after the discrete $$ {\mathcal{Z}}_2^{\prime } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>Z</mml:mi> <mml:mn>2</mml:mn> <mml:mo>′</mml:mo> </mml:msubsup> </mml:math> symmetry gets softly broken, while the unbroken $$ {\mathcal{Z}}_2 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>Z</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> keeps the dark matter stable. The mixing between the singlet ψ and the doublet vector lepton can be constrained to satisfy the electroweak precision observables and the spin independent (SI) direct detection (DD) cross section of the dark matter. In this analysis, potentially important LHC bounds have also been discussed.