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Register a new userDead or Alive? Implications of the Muon Anomalous Magnetic Moment for 3-3-1 Models
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We have witnessed a persistent puzzling anomaly in the muon magnetic moment that cannot be accounted for in the Standard Model even considering the large hadronic uncertainties. A new measurement is forthcoming, and it might give rise to a $5sigma$ claim for physics beyond the Standard Model. Motivated by it, we explore the implications of this new result to five models based on the $SU(3)_C times SU(3)_L times U(1)_N$ gauge symmetry and put our conclusions into perspective with LHC bounds. We show that previous conclusions found in the context of such models change if there are more than one heavy particle running in the loop. Moreover, having in mind the projected precision aimed by the g-2 experiment at FERMILAB, we place lower mass bounds on the particles that contribute to muon anomalous magnetic moment assuming the anomaly is resolved otherwise. Lastly, we discuss how these models could accommodate such anomaly in agreement with existing bounds.
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We investigate the muon anomalous magnetic moment in the context of the supersymmetric version of the economical 3-3-1 model. We compute the 1-loop contribution of super-partner particles. We show that contribution of superparticle loop becomes significant when tan gamma is large. We investigate for both small and large values of $tan gamma$. We find the region of the parameter space where the slepton masses are of a few hundreds GeV is favour by the muon g-2 for small tan gamma (tan gamma sim 5 ). Numerical estimation gives the mass of supersymmetric particle, the mass of gauginos m_G sim 700 GeV and light slepton mass m_{tilde{L}} is of order O (100) GeV. When tan{gamma} is large (tan{gamma} sim 60), the mass of charged slepton m_{tilde{L}} and the mass of gauginos m_Gsim O(1) TeV while the mass of sneutrino sim 450 GeV is in the reach of LHC.
We calculate, in the context of a 3-3-1 model with heavy charged leptons, constraints on some parameters of the extra particles in the model by imposing that their contributions to both the electron and muon $(g-2)$ factors are in agreement with experimental data up to 1$sigma$-3$sigma$. In order to obtain realistic results we use some of the possible solutions of the left- and right- unitary matrices that diagonalize the lepton mass matrices, giving the observed lepton masses and at the same time allowing to accommodate the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. We show that, at least up to 1-loop order, in the particular range of the space parameter that we have explored, it is not possible to fit the observed electron and muon $(g-2)$ factors at the same time unless one of the extra leptons has a mass of the order of 20-40 GeVs and the energy scale of the 331 symmetry to be of around 60-80 TeVs.
The parity violation in cesium atom is analysed in the framework of the models based on the SU(3)_C X SU(3)_L X U(1)_N gauge group. It is shown that in the minimal version, the main contribution to a deviation of weak charge Delta Q_W due to direct Z exchange is negative. New data on parity violation in the cesium atom seems not favour to the minimal version, while it gets a positive value in the version with right-handed neutrinos. We obtain a bound on the $Z$ mass at a range from 1.4 TeV to 2.6 TeV. The allowed regions for the Z-Z$mixing angle are also derived.
A new QCD sum rule determination of the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, $a_{mu}^{rm hvp}$, is proposed. This approach combines data on $e^{+}e^{-}$ annihilation into hadrons, perturbative QCD and lattice QCD results for the first derivative of the electromagnetic current correlator at zero momentum transfer, $Pi_{rm EM}^prime(0)$. The idea is based on the observation that, in the relevant kinematic domain, the integration kernel $K(s)$, entering the formula relating $a_{mu}^{rm hvp}$ to $e^{+}e^{-}$ annihilation data, behaves like $1/s$ times a very smooth function of $s$, the squared energy. We find an expression for $a_{mu}$ in terms of $Pi_{rm EM}^prime(0)$, which can be calculated in lattice QCD. Using recent lattice results we find a good approximation for $a_{mu}^{rm hvp}$, but the precision is not yet sufficient to resolve the discrepancy between the $R(s)$ data-based results and the experimentally measured value.
The CP violating two-Higgs doublet model of type-X may enhance significantly the electric and magnetic moment of leptons through two-loop Barr-Zee diagrams. We analyze the general parameter space of the type-X 2HDM consistent with the muon $g-2$ and the electron EDM measurements to show how strongly the CP violating parameter is constrained in the region explaining the muon $ g-2$ anomaly.
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