Interdependence of the new 'MUON G-2' Result and the $W$-Boson Mass

Bagnaschi, E.; Heinemeyer, S.; Chakraborti, M.; Saha, I.; Weiglein, G.

Preprint

PUBDB-2022-01418

Interdependence of the new 'MUON G-2' Result and the $W$-Boson Mass

Bagnaschi, E. (Corresponding author)Extern* ; Chakraborti, M. ; Heinemeyer, S. ; Saha, I. ; Weiglein, G.DESY*

2022

[10.3204/PUBDB-2022-01418]

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Please use a persistent id in citations: doi:10.3204/PUBDB-2022-01418

Report No.: CERN-TH-2022-034; DESY-22-041; IFT-UAM/CSIC-22-029; arXiv:2203.15710

Abstract: The electroweak (EW) sector of the Minimal Supersymmetric extension of the Standard Model (MSSM), assuming the lightest neutralino as Dark Matter (DM) candidate, can account for a variety of experimental results. In particular it can account for the discrepancy between the experimental result for the anomalous magnetic moment of the muon, $(g-2)_{\mu}$, and its Standard Model (SM) prediction. The new 'MUON G-2' result, combined with the older BNL result on $(g-2)_{\mu}$, yields a deviation from the SM prediction of $\Delta a_{\mu} = (25.1 \pm 5.9) \times 10^{-10}$, corresponding to $4.2~\sigma$. Using this updated bound, together with the other constraints, we calculate the MSSM prediction for the mass of the $W$ boson, $M_W$. We assume contributions only from the EW sector, with the colored sector of the MSSM taken to be heavy. We investigate five scenarios, distinguished by the mechanisms which yield a relic DM density in agreement with the latest Planck bounds. We find that with the new $(g-2)_{\mu}$ result taken into account and depending on the scenario, values up to $M_W^{\mathrm{MSSM}} \lesssim 80.376~\mathrm{GeV}$ are reached. The largest values are obtained for wino DM and in the case of slepton co-annihilation, where points well within the $1\,\sigma$ range of the experimental world average of $M_W^{\mathrm{exp}} = 80.379 \pm~0.012~\mathrm{GeV}$ are reached, whereas the SM predicts a too small value of $M_W^{\mathrm{SM}} = 80.353~\mathrm{GeV}$. We analyze the dependence of $M_W^{\mathrm{MSSM}}$ on the relevant masses of the EW superpartners and demonstrate that future $M_W$ measurements, e.g. at the ILC, could distinguish between various MSSM realizations. Sizable contributions to $M_W^{\mathrm{MSSM}}$ are associated with a relatively light $\tilde{\chi}^0_1$, accompanied by either a light chargino or a light smuon, setting interesting targets for future collider searches.

Keyword(s): muon, magnetic moment ; dark matter, density ; minimal supersymmetric standard model ; GeV ; experimental results ; sparticle ; neutralino ; slepton ; electroweak interaction ; Planck ; ILC Coll ; chargino ; smuon ; Brookhaven Lab