We present a search for pair production of doubly charged Higgs bosons in the processes $q\overline{q}\to H^{++}{H}^{--}$ decaying through $H^{\pm \pm }\to {\tau }^{\pm }{\tau }^{\pm },{\mu }^{\pm }{\tau }^{\pm },{\mu }^{\pm }{\mu }^{\pm }$. The search is performed in $p\overline{p}$ collisions at a center-of-mass energy of $\sqrt{s}=1.96\mathrm{TeV}$ using an integrated luminosity of up to $7.0{\mathrm{fb}}^{-1}$ collected by the D0 experiment at the Fermilab Tevatron Collider. The results are used to set 95% C.L. limits on the pair production cross section of doubly charged Higgs bosons and on their mass for different $H^{\pm \pm }$ branching fractions. Models predicting different $H^{\pm \pm }$ decays are investigated. Assuming $\mathcal{B}(H^{\pm \pm }\to {\tau }^{\pm }{\tau }^{\pm })=1$ yields an observed (expected) lower limit on the mass of a left-handed $H_L^{\pm \pm }$ boson of 128 (116) GeV and assuming $\mathcal{B}(H^{\pm \pm }\to {\mu }^{\pm }{\tau }^{\pm })=1$ the corresponding limits are 144 (149) GeV. In a model with $\mathcal{B}(H^{\pm \pm }\to {\tau }^{\pm }{\tau }^{\pm })=\mathcal{B}(H^{\pm \pm }\to {\mu }^{\pm }{\tau }^{\pm })=\mathcal{B}(H^{\pm \pm }\to {\mu }^{\pm }{\mu }^{\pm })=1/3$, we obtain $M(H_L^{\pm \pm })>130(138)\mathrm{GeV}$.

• Received 22 June 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.021801