Funnel annihilations of light dark matter and the invisible decay of the Higgs boson
Kun Wang, Jingya Zhu
Abstract
The semiconstrained NMSSM (scNMSSM), or the next-to minimal supersymmetric standard model (NMSSM) with nonuniversal Higgs masses, can naturally predict a light dark matter under current constraints including Higgs data, sparticle-mass bounds, dark matter searches, muon g-2, etc. In this work, we take this scenario of scNMSSM as an example to study the funnel-annihilation mechanisms of light dark matter (1--62 GeV) and the invisible Higgs decay. In this scenario, we found that (i) there can be four funnel-annihilation mechanisms for the lightest supersymmetric particle ${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}$, which are ${h}_{2}$, $Z$, ${h}_{1}$, and ${a}_{1}$ funnel. (ii) For the ${h}_{1}$ and ${a}_{1}$ funnel with right relic density, the ${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}$ mass is lighter than 12 GeV, and the invisible Higgs decay can be 2% at most. (iii) For the ${h}_{2}$ and $Z$ funnel with right relic density, the invisible Higgs decay can be about 0.4% and 1%, respectively, at most. (iv) If the invisible Higgs decay was discovered at the HL-LHC, the four funnel-annihilation mechanisms of light dark matter may be all excluded with ${\stackrel{\texttildelow{}}{\ensuremath{\chi}}}_{1}^{0}$ as the only dark matter source. Four benchmark points, one for each mechanism, are proposed for future checking with updated experimental results.