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, $a_{\mu }=(g-2{)}_{\mu }/2$, in the Doublet Left-Right Symmetric Model (DLRSM), based on the gauge group $SU(2{)}_L\otimes SU(2{)}_R\otimes U(1{)}_{B-L}$ 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 ($W^{\prime }$, $Z^{\prime }$), the new scalar sector ($H_3^0$, $A_1^0$, $H_R^{\pm }$, $H_L^{\pm }$), 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 $\Delta a_{\mu }$, we establish that $v_R\lesssim 1$ TeV is excluded, implying lower bounds $m_{W^{\prime }}\gtrsim 325$ GeV, $m_{Z^{\prime }}\gtrsim 385$ GeV, and $m_N\gtrsim 700$ GeV under the manifest left-right symmetry condition $g_R=g_L$. Relaxing this condition to $g_R\ne g_L$ strengthens the gauge boson bounds to $m_{W^{\prime }}\gtrsim 1625$ GeV and $m_{Z^{\prime }}\gtrsim 1650$ GeV.

Comments: 17 pages, 5 figures