New physics explanations of $a_μ$ in light of the FNAL muon $g-2$ measurement

Abstract

The Fermilab Muon g − 2 experiment recently reported its first measurement of the anomalous magnetic moment a FNAL µ , which is in full agreement with the previous BNL measurement and pushes the world average deviation ∆a 2021 µ from the Standard Model to a significance of 4.2σ. Here we provide an extensive survey of its impact on beyond the Standard Model physics. We use state-of-the-art calculations and a sophisticated set of tools to make predictions for a µ , dark matter and LHC searches in a wide range of simple models with up to three new fields, that represent some of the few ways that large ∆a µ can be explained. In addition for the particularly well motivated Minimal Supersymmetric Standard Model, we exhaustively cover the scenarios where large ∆a µ can be explained while simultaneously satisfying all relevant data from other experiments. Generally, the a µ result can only be explained by rather small masses and/or large couplings and enhanced chirality flips, which can lead to conflicts with limits from LHC and dark matter experiments. Our results show that the new measurement excludes a large number of models and provides crucial constraints on others. Two-Higgs doublet and leptoquark models provide viable explanations of a µ only in specific versions and in specific parameter ranges. Among all models with up to three fields, only models with chirality enhancements can accommodate a µ and dark matter simultaneously. The MSSM can simultaneously explain a µ and dark matter for Bino-like LSP in several coannihilation regions. Allowing under abundance of the dark matter relic density, the Higgsino-and particularly Wino-like LSP scenarios become promising explanations of the a µ result.

Heavy singly charged Higgs bosons and inverse seesaw neutrinos as origins of large $(g-2)_{e,μ}$ in two higgs doublet models

“…The Yukawa couplings of Higgs bosons with heavy fermions will be constrained by the perturbative limits, for example 0. in a rather narrow allowed region of parameter space at the price of imposing dangerous requirements that can be experimentally tested in the near future [57,63]. The conclusion is also true for the Minimal supersymmetric model MSSM [64][65][66]. As usual solution, there is a variety of extensions of THDM that successfully explain and accommodate the (g − 2) e,µ anomalies by adding new vector-like fermions as SU (2) L multiplets [38][39][40][41][42][43] as well as SU (2) L singlets of neutral and charged Higss bosons [54,56,[68][69][70][71].…”

Two-to-two processes at an electron-muon collider

“…there are really only three non-equivalent amplitudes in this study: [12][34], [13][24] and [14] Λ 2 factor to be included. The R, L indices refer to chiralities.…”

“…lequ , Q leqd3 and the σ ++ contribution of Q T le generate the same amplitude [13][24] + [14] [23]. Except for the v 4 /(4Λ 4 ) additional factor the cross sections are equal.…”

Constraining Light Mediators via Detection of Coherent Elastic Solar Neutrino Nucleus Scattering

“…The Muon (g − 2) Collaboration at Fermi National Laboratory [83] has just published a new result on the anomalous muon magnetic moment, and when combined with the old result from Brookhaven National Laboratory [84], induces 4.2σ inconsistency with the SM prediction [85]. Among the numerous and diverse solutions [86,87] to the muon (g − 2) anomaly, the light vector mediator with the L µ − L τ gauge symmetry is regarded as a viable and simple model [88][89][90][91]. In this regard, we are going to investigate the L µ − L τ model using the coherent elastic solar neutrino nucleus scattering in current and future direct detection experiments in this work.…”