A 2HDM for the g-2 and Dark Matter

Abstract

The Muon g-2 experiment at FERMILAB has confirmed the muon anomalous magnetic moment anomaly with an error bar 15% smaller and a different central value compared with the previous Brookhaven result. The combined results from FERMILAB and Brookhaven show a difference with theory at a significance of 4.2σ, strongly indicating the presence of new physics. In light of this new result, we discuss a Two Higgs Doublet model augmented by an Abelian gauge symmetry that can simultaneously accommodate a light dark matter candidate and (g − 2)µ, in agreement with existing bounds.

Effects of 2HDM in electroweak phase transition

“…At tree level QED, the gyromagnetic ratio of muon is g µ = 2. Adding virtual particles and loop corrections, the calculated value of g µ − 2 /2 in SM is 116591810(43) × 10 −11 while the measured value from FERMILAB is 116592061(41) × 10 −11 [2,3]. The detection of this anomaly actually has buttressed the previous claims about the disaccord between the theoretical and experimental results [4].…”

A Direct Detection Search for Hidden Sector New Particles in the 3-60 MeV Mass Range

“…There are many proposed solutions to this discrepancy, here we will focus on potential MeV-scale bosons leading to loop corrections that can account for the muons' anomalous magnetic moment. For example the scalar Higgs doublet model which adds a second scalar doublet to the SM, resulting in a scalar sector with two Higgs doublets [12]. The muon couples directly to the new Z gauge boson which can provide the required contribution to the muon g − 2.…”

“…The muon couples directly to the new Z gauge boson which can provide the required contribution to the muon g − 2. In fact, the Z can be made very light with a sufficiently small coupling constant g and can address the (g − 2) µ anomaly with Z mass roughly in the range of 10 -200 MeV [12], as shown in Fig. 3.…”

“…The DM relic abundance constrains the allowed phase space to near the Z resonance, which implies m X ∼ m Z /2. If the Z mass should lie around 10 -200 MeV to explain the (g − 2) µ the DM mass must lie in the mass range m X ≈ 5 -100 MeV [12]. The X can also directly contribute to the (g − 2) µ .…”

Phenomenology of a flavoured multiscalar BGL-like model with three generations of massive neutrinos

“…This type of models provide a rich breeding ground for phenomenological studies, with the possibility of having a suitable DM candidate in its spectrum [4][5][6][7][8][9], spontaneous CPviolation [10][11][12][13][14] and generation of flavour-changing neutral currents (FCNCs) mediated by the new neutral scalars [15,16]. However, the presence of FCNCs can be troublesome since they are very constrained experimentally, and in the models we are discussing they can manifest themselves already at tree-level, whereas equivalent processes in the SM are of pure radiative origin, thus highly suppressed.…”