The new "MUON G-2" Result and Supersymmetry

TL;DR

The paper updates constraints on the MSSM's electroweak sector using the latest muon g-2 results, confirming that key supersymmetric particles are within reach of future collider searches.

Contribution

It provides new upper limits on MSSM electroweak particles based on the recent muon g-2 measurement, refining the parameter space for supersymmetry models.

Findings

Upper limits on SUSY particle masses are around 600 GeV.

The new muon g-2 result reduces the discrepancy with the SM to 4.2 sigma.

Future colliders can probe the constrained MSSM parameter space.

Abstract

The electroweak (EW) sector of the Minimal Supersymmetric Standard Model (MSSM), with the lightest neutralino as Dark Matter (DM) candidate, can account for a variety of experimental data. This includes the DM content of the universe, DM direct detection limits, EW SUSY searches at the LHC and in particular the so far persistent $3-4\,\sigma$ discrepancy between the experimental result for the anomalous magnetic moment of the muon, $(g-2)_\mu$, and its Standard Model (SM) prediction. The recently published ``MUON G-2'' result is within $0.8\,\sigma$ in agreement with the older BNL result on $(g-2)_\mu$. The combination of the two results was given as $a_\mu^{\rm exp} = (11 659206.1 \pm 4.1c) \times 10^{-10}$, yielding a new deviation from the SM prediction of $\Delta a_\mu = (25.1 \pm 5.9) \times 10^{-10}$, corresponding to $4.2\,\sigma$. Using this improved bound we update the results presented in [1] and set new upper limits on the allowed parameters space of the EW sector of the MSSM. We find that with the new $(g-2)_\mu$ result the upper limits on the (next-to-) lightest SUSY particle are in the same ballpark as previously, yielding updated upper limits on these masses of $\sim 600$ GeV. In this way, a clear target is confirmed for future (HL-)LHC EW searches, as well as for future high-energy $e^+e^-$ colliders, such as the ILC or CLIC.