Implications of the muon anomalous magnetic moment in a doublet left-right symmetric model

Abstract

We compute the complete set of one-loop contributions to the muon anomalous magnetic moment,

, in the doublet left-right symmetric model (DLRSM), based on the gauge group

$$SU(2)_{L}\otimes SU(2)_{R}\otimes U(1)_{B-L}$$ S U ( 2 ) L ⊗ S U ( 2 ) R ⊗ U ( 1 ) B - L

with neutrino masses generated via the inverse seesaw (ISS) mechanism. We evaluate all four one-loop topologies VFF, SFF, FVV, and FSS arising from the extended gauge bosons (

$$W^{\prime }$$ W ′

,

$$Z^{\prime }$$ Z ′

), the new scalar sector (

$$H_{3}^{0}$$ H 3 0

,

$$A_{1}^{0}$$ A 1 0

,

$$H_{R}^{\pm }$$ H R ±

,

$$H_{L}^{\pm }$$ H L ±

), and the heavy neutrino spectrum generated by the ISS mechanism, using the Casas–Ibarra parametrization to express the neutrino mixing in terms of physical observables. Imposing the experimental bound on

$$\varDelta a_{\mu }$$ Δ a μ

, we find a lower bound

$$v_{R} > rsim 1$$ v R ≳ 1

TeV, corresponding to

$$m_{W^{\prime }} > rsim 325$$ m W ′ ≳ 325

GeV,

$$m_{Z^{\prime }} > rsim 385$$ m Z ′ ≳ 385

GeV, and

$$m_{N} > rsim 700$$ m N ≳ 700

GeV under the manifest left-right symmetry condition

$$g_{R}=g_{L}$$ g R = g L

(strengthened to

$$m_{W^{\prime }} > rsim 1625$$ m W ′ ≳ 1625

GeV and

$$m_{Z^{\prime }} > rsim 1650$$ m Z ′ ≳ 1650

GeV for

$$g_{R}\ne g_{L}$$ g R ≠ g L

). This bound lies well below the existing flavor and direct-collider limits, so the muon

$$g-2$$ g - 2

provides a sub-leading and complementary constraint on the DLRSM.