Search for doubly charged higgs boson pair production in $p\bar p$ collisions at $\sqrt s=1.96\ \text{TeV}$

Abstract

We present a search for pair production of doubly charged Higgs bosons in the processes $q\bar q→H^{++}H^{−−}$ decaying through $H^{±±}→τ^±τ^±,μ^±τ^±,μ^±μ^±$. The search is performed in pp¯ collisions at a center-of-mass energy of $\sqrt s=1.96 \text{TeV}$ using an integrated luminosity of up to $7.0 \text{fb}^{−1}$ 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 $H^{±±}$ branching fractions. Models predicting different $H^{±±}$ decays are investigated. Assuming $\mathscr{B}(H^{±±}→τ^±τ^±)=1$ yields an observed (expected) lower limit on the mass of a left-handed $H^{±±}_L$ boson of 128 (116) GeV and assuming $\mathscr{B}(H^{±±}→μ^±τ^±)=1$ the corresponding limits are 144 (149) GeV. In a model with $\mathscr{B}(H^{±±}→τ^±τ^±)=\mathscr{B}(H^{±±}→μ^±τ^±)=\mathscr{B}(H^{±±}→μ^±μ^±)=1/3$, we obtain $M(H^{±±}_L)>130 (138) \text{GeV}$.