Resolving the W boson mass in the lepton specific two Higgs doublet model

Abstract

In 2022, the collider detector at Fermilab (CDF) collaboration reported the W-boson mass (M-W = 80.4335 +/- 0.0094 GeV), which deviates from the standard model (SM) prediction (M-W(SM) = 80.357 +/- 0.006 GeV) by similar to 7 sigma. In contrast, the CMS collaboration obtained M-W = 80.3602 +/- 0.0099 GeV, which was very close to the SM global electroweak fit value of similar to 80.357 GeV. Motivated by this situation, we reassess the W-boson mass within the lepton-specific two Higgs doublet model (LS-2HDM). To this end, we perform random scans (generated with SARAH 4.13.0 and evaluated with SPheno 4.0.3) and confront the results with up-to-date theoretical and experimental constraints. The scan enforces vacuum stability, perturbative unitarity, and perturbativity; electroweak precision observables via the oblique parameters (S,T,U); LEP bounds on H-+/-; rare B-meson decays; lepton flavor universality (LFU) in Z and tau decays; and 13 TeV LHC searches for additional Higgs bosons. Viable points are further tested with HiggsTools (HiggsSignals + HiggsBounds). In the LS-2HDM, if h(1) is the SM-like Higgs at m(h1) similar or equal to 125 |cos((beta-alpha))|less than or similar to 0.06, 17 less than or similar to tan beta less than or similar to 39, 144 less than or similar to m(h2) less than or similar to 414 GeV, and 435 less than or similar to m(A,H) +/- less than or similar to 685 GeV, the model reproduces the 2024 CMS W-boson mass within 3 sigma. Solutions near the 2022 CDF value (M-W = 80.4335 +/- 0.0094 GeV) survive; however, after applying all constraints, including HiggsTools, they approach it at best within less than or similar to 2 sigma. Our findings emphasize that LS-2HDM favors the CMS results consistently with the current experimental results. Although one can theoretically accommodate the CDF results in this model, up-to-date electroweak precision bounds on oblique parameters (S,T,U) with the SM-like Higgs and LFU constraints exclude these solutions. Our results for W-boson mass can only be as close as about 2 sigma to the CDF results.