Connecting the Muon Anomalous Magnetic Moment and the Multi-lepton Anomalies at the LHC

TL;DR

This paper explores connections between the muon g-2 anomaly and multi-lepton signals at the LHC, proposing a 2HDM+S model with additional fermions to explain the observed discrepancies.

Contribution

It introduces a 2HDM+S framework with fermions that links muon g-2 and multi-lepton anomalies, extending previous models with new particles and interactions.

Findings

2HDM+S alone cannot explain muon g-2 discrepancy

Adding fermions of ~100 GeV can account for the muon g-2 anomaly

Heavy boson H decays into Higgs and scalar S are consistent with multi-lepton data

Abstract

A number of predictions were made in von Buddenbrock et al (2016 Eur. Phys. J. C 76, 10, 580) pertaining to the anomalous production of multiple leptons at the Large Hadron Collider. Discrepancies in multi-lepton final states have now become statistically compelling with the available Run~2 data. These could be connected with a heavy boson, $H$, decaying predominantly into a SM Higgs boson, $h$, and a singlet scalar, $S$, where $m_H\approx 270$\,GeV and $m_S\approx 150$\,GeV. These can be embedded into a scenario where a Two Higgs Doublet is considered with an additional singlet scalar, 2HDM+S. The long-standing discrepancy in the muon anomalous magnetic moment, $\Delta a_\mu$, is interpreted in the context of the 2HDM+S type-II and type-X, along with additional fermionic degrees of freedom. The 2HDM+S model alone with the constraints from the LHC data does not seem to explain the $\Delta a_\mu$ anomaly. However, adding fermions with mass of order $\mathcal{O}(100)$\,GeV can explain the discrepancy for low enough values of fermion-scalar couplings.