Dark matter physics in dark $SU(2)$ gauge symmetry with non-Abelian kinetic mixing

Abstract

We investigate a model of dark sector based on non-Abelian $SU(2{)}_D$ gauge symmetry. This dark gauge symmetry is broken into discrete $Z_2$ via vacuum expectation values of two real triplet scalars, and an $SU(2{)}_D$ doublet Dirac fermion becomes $Z_2-$odd particles whose lighter component makes stable dark matter candidate. The standard model and dark sector can be connected via the scalar mixing and the gauge kinetic mixing generated by higher dimensional operators. We then discuss relic density of dark matter and implications to collider physics in the model. The most unique signatures of this model at the LHC would be the dark scalar (${\Phi }_1^{{(}^{\prime })}$) productions where it subsequently decays into : (1) a fermionic dark matter (${\chi }_l$) and a heavy dark fermion (${\chi }_h$) pair, ${\Phi }_1^{{(}^{\prime })}\to {\bar{\chi }}_l{\chi }_h({\bar{\chi }}_h{\chi }_l)$, followed by ${\chi }_h$ decays into ${\chi }_l$ and non-Abelian dark gauge bosons ($X_i$'s) which decays into SM fermion pair ${\bar{f}}_{SM}{f}_{SM}$ resulting in the reaction $pp\to {\Phi }_1^{{(}^{\prime })}\to {\bar{\chi }}_h{\chi }_l({\bar{\chi }}_l{\chi }_h)\to f_{SM}{\bar{f}}_{SM}{\chi }_l{\bar{\chi }}_l$, (2) a pair of $X_i$'s followed by $X_i$ decays into a DM pair or the SM fermions resulting in the reaction, $pp\to {\Phi }_1^{{(}^{\prime })}\to X_i{X}_i\to {\bar{\chi }}_l{\chi }_l{f}_{SM}{\bar{f}}_{SM}$ or even number of $f_{SM}{\bar{f}}_{SM}$ pairs.

Comments: 20 pages, 5 figures