The 28 GeV dimuon excess in lepton specific THDM

Abstract

We explore the Higgs mass spectrum in a class of Two Higgs Doublet Models (THDMs) in which a scalar SU(2)Ldoublet interacts only with quarks, while the second one interacts only with leptons. The spectrum includes two CP-even Higgs bosons, either of which can account for the SM-like Higgs boson, and the spectra involving light Higgs bosons receive strong impacts from the LEP results and the current collider analyses. We find that a consistent spectrum can involve a CP-odd Higgs boson as light as about 10 GeV, while the lightest CP-even Higgs boson cannot be lighter than about 55 GeV when mA∼28GeV. These analyses can rather bound the low tanβregion which can also accommodate an observed excess in dimuon events at mμμ∼28GeV. A lepton-specific class of THDMs (LS-THDM) can predict such an excess through A →μμdecays, while the solutions can be constrained by the A →ττmode. After constraining the solutions with the consistent ranges of σ(pp→bbA →bbττ), a largest excess at about 1.5σat 8 TeV center of mass (COM) energy and 2σat 13 TeV COM is observed for tanβ∼12and mA∼28GeV in the σ(pp→bbA →bbμμ)events