Long-lived dark Higgs and inelastic dark matter at Belle II

Inelastic dark matter is an interesting scenario for light thermal dark matter which is fully consistent with all cosmological probes as well as direct and indirect dark matter detection. The required mass splitting between dark matter χ1 and its heavier twin χ2 is naturally induced by a dark Higgs field which also provides a simple mechanism to give mass to the dark photon A′ present in the setup. The corresponding dark Higgs boson h′ is naturally the lightest dark sector state and therefore decays into Standard Model particles via Higgs mixing. In this work we study signatures with displaced vertices and missing momentum at Belle II, arising from dark Higgs particles produced in association with dark matter. We find that Belle II can be very sensitive to this scenario, in particular if a displaced vertex trigger is available in the near future.

A Simple Technique to Infer the Missing Gravity Wave Drag in the Middle Atmosphere Using a General Circulation Model: Potential Vorticity Budget

A simple technique to infer the missing momentum forcing in a general circulation model is developed and evaluated. The response of the large-scale dynamic equations to an external momentum forcing presents a nonlocal response in the zonal and meridional wind. On the other hand, the response to the external momentum forcing in the potential vorticity (PV) is a local growing geostrophic mode, so that there is a direct relationship between the external momentum forcing and the response in PV. In this work, this fact is exploited to diagnose the missing momentum forcing in the extratropics using a general circulation model. The capability of the simple technique to estimate a concentrated gravity wave forcing is evaluated. A dynamical model is evolved with prescribed sources and sinks of PV and then the technique is used to estimate these known momentum sources and sinks. PV is found to give a much better diagnostic of gravity wave drag compared to the more traditional zonal wind differences. The technique is also used in a realistic environment, in which the sources and sinks of PV in Met Office analyses are determined. The estimation of this missing forcing with this simple technique is compared with the estimation given by a more complex data assimilation technique developed by Pulido and Thuburn and, in general, a good agreement is found. The simple gravity wave drag estimation technique can be used in an online data assimilation cycle, using the increments of the analysis, and also offline, using a general circulation model and observations.