Search for Dark Matter associated with b-anti-b quark production

The DESY Exotics group intends to perform searches for dark matter particles produced in association with a bottom-quark pair at Run-2.

Dark Matter that interacts with the visible sector in particular via a scalar or pseudoscalar mediator is an appealing scenario, in particular in association with the production of a pair of heavy quarks. We analyse already the production of Dark Matter particles in association with a top quark pair. If the Dark Matter mediator which mediates the interaction between ordinary matter and Dark Matter particles is either a scalar or a pseudoscalar particle and the coupling would be Yukawa-like it would couple strongest to top quarks of all Standard Model particles. Second largest would be the coupling to bottom-quarks investigated here. If the Dark Matter mediator is a sibling of the Z boson, a Z' particle, with the same vector/axial vector couplings to quarks as given by the Standard Model, one would find it sooner in association with b-quarks than with top-quarks, because the cross section would be larger and the couplings similar. Therefore this search for Dark Matter particles produced in association with a b- and an anti-b-quark as shown in Figure 1 is particularly interesting.

The DESY-CMS Standard Model Physics group is already performing a measurement of di-b-jet production. This analysis shall be used to ask for additional missing transverse momentum coming from the Dark Matter particles which leave the detector undetected.

First studies of interesting variables that can separate the signal (see Figure 1) from Standard Model di-b-jet production can be done as a Bachelor or Master thesis. The full analysis of the Run-II CMS dataset could be done as a PhD thesis.