Speaker
Mikael Berggren
(Deutsches Elektronen-Synchrotron (DE))
Description
It is an appealing possibility that the observed dark matter density in
the universe can be fully explained by SUSY. The current experimental
knowledge indicates that this possibility favours a
co-annihilation scenario. In such scenarios, the mass difference between
the next-to-lightest SUSY particle (the NLSP) and the lightest one (the
LSP) is quite small, which assures that the annihilation cross-section
is sufficient not to predict a too large abundance of dark matter.
However, the small mass difference also means that observing SUSY
becomes hard at hadron colliders, where the observation hinges on the
tell-tale signature of missing transverse energy: if the mass difference NLSP-to-LSP is
small, only little energy is carried away by the invisible LSP. This is
also true even if several other SUSY particles are within the kinematic
reach, since these states would to a large extent decay via
cascades ending with an NLSP to LSP decay. A lepton collider does not
have this problem. The clean environment and known initial state at such
machines assures that SUSY can be detected even if the mass difference
is very small, provided the centre-of-mass energy is sufficiently high.
We present
prospects for observation and precision characterisation of SUSY with
small mass differences at the ILC, based on detailed simulations
of the ILD detector concept. The resulting possibility to predict the
dark matter relic density is evaluated and compared to the
precision obtained from the Planck mission. Taking a specific model as an
example, we also discuss the synergies from combining ILC and HL-LHC
results.
Primary author
Mikael Berggren
(Deutsches Elektronen-Synchrotron (DE))
