First constraint on the mass of doubly-charged Higgs bosons in the same-sign diboson decay scenario at the LHC

TL;DR

This paper establishes new lower bounds on the mass of doubly-charged Higgs bosons decaying into same-sign dibosons at the LHC, improving previous constraints and exploring LEP data limitations.

Contribution

It provides the first experimental mass bounds for doubly-charged Higgs bosons in the diboson decay scenario using current LHC data.

Findings

Lower mass bound of 60 GeV at 95% C.L. from LHC data

Projected lower bound of 85 GeV with increased luminosity

LEP data exclude masses below 43 GeV based on Z width measurements

Abstract

When the doubly-charged Higgs bosons $H^{\pm\pm}$ mainly decay into the same-sign dilepton, a lower bound on the mass is around 400 GeV by the current LHC data. On the other hand, no such bound has been reported by using the data at LEP and at the LHC for the case where the same-sign diboson decay $H^{\pm\pm}\to W^{\pm(*)} W^{\pm(*)}$ is dominant. We study limits on the mass for such a case by using the current experimental data. From the precise measurement of the total width of the Z boson at the LEP experiment, the mass below 43 GeV is excluded with the 95% C.L. It turns out that the results from four charged lepton searches at LEP do not provide any significant constraint. We show that a new lower bound is obtained in the diboson decay scenario at the LHC with the collision energy to be 7 TeV and the integrated luminosity to be 4.7 fb$^{-1}$. By using the data of the same-sign dilepton events, the lower limit is found to be 60 GeV at the 95% C.L. By the extrapolation of the data to 20 fb$^{-1}$ with the same collision energy, the lower limit is evaluated to be 85 GeV.