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Abstract:
We present a scenario for GeV-scale thermal dark matter that can only be tested with accelerator experiments. Dark matter is composed of dark pions arising from a confining strong interaction in the dark sector.The thermal relic density is obtained through the interplay of up-scatterings of dark pions to heavier dark mesons (the dark counterparts of the kaons and $\eta$), and decays of the unstable dark $\eta$ to Standard Model particles. This mechanism is analogous to a playground slide, where one climbs up first and then slides down with a release of energy. We illustrate the scenario with a minimal model based on the $SU(3)/SO(3)$ coset, where dark matter is stabilized by a $U(1)$ flavor symmetry. The correct relic density is obtained with dark meson mass splittings of $10\%$ to $50\%$ and a dark-$\eta$ lifetime shorter than $10^3\,\mathrm{m}/c$. Direct and indirect dark matter searches are mostly ineffective, as a consequence of the charge conjugation symmetry of the stabilizing $U(1)$. The most striking signals arise at the LHC, from the production of dark showers containing long-lived dark $\eta$’s that decay to visible final states. These signatures crucially depend on the portal interaction connecting the dark sector to the Standard Model. We show that several well-known portals can complete the scenario above the weak scale,and outline the expected signals in each case.
Biography：
Lingfeng Li graduated from Peking University in 2013 and received his PhD in Theoretical High Energy Physics from the University of California, Davis in 2018 under the supervision of Prof. Hsin-Chia Cheng. Then he worked at HKUST and Brown University as a Postdoctoral Researcher. He is interested in precision tests of the Standard Model and probing new physics with new models, methods, and mindsets.
Alternative online link: https://meeting.tencent.com/dm/PNtk4dyG384d
ID: 810937353