hep-ex updates on arXiv.org


Probing the Dark Axion Portal with Muon Anomalous Magnetic Moment. (arXiv:2104.03276v2 [hep-ph] UPDATED)

We propose a new scenario of using the dark axion portal to explain the observed muon anomalous magnetic moment, $(g-2)_\mu$, at the one-loop level. Both axion/axion-like particle (ALP) and dark photon are involved in the same vertex with photon. Although ALP or dark photon alone cannot explain muon $g-2$, since the former can only provide negative contribution while the latter has very much constrained parameter space, dark axion portal can save the situation and significantly extend the allowed parameter space. The observed muon anomalous magnetic moment provides a robust probe of the dark axion portal scenario.

Confronting spin-3/2 and other new fermions with the muon g-2 measurement. (arXiv:2104.03231v2 [hep-ph] UPDATED)

The new measurement of the muon's anomalous magnetic moment released by the Muon g-2 experiment at Fermilab sets strong constraints on the properties of many new particles. Using an effective field theory approach to the interactions of higher-spin fields, we evaluate the contribution of an electrically neutral and colour singlet spin-3/2 fermion to $(g-2)_\mu$ and derive the corresponding constraints on its mass and couplings. These constraints are then compared with the ones on spin-1/2 fermions, such as the vector-like leptons that are predicted by various extensions of the Standard Model, the excited leptons which appear in composite models, as well as the charginos and neutralinos of supersymmetric theories. Unlike these new spin-1/2 fermions, the spin-3/2 particles generate only small contributions to the muon anomalous magnetic moment.

Wino-Higgsino dark matter in the MSSM from the $g-2$ anomaly. (arXiv:2104.03223v2 [hep-ph] UPDATED)

In this letter, we show that the wino-Higgsino dark matter (DM) is detectable in near future DM direct detection experiments for almost all consistent parameter space in the spontaneously broken supergravity (SUGRA) if the muon g-2 anomaly is explained by the wino-Higgsino loop diagrams. We also point out that the present and future LHC experiments can exclude or confirm this SUGRA explanation of the observed muon g-2 anomaly.