Studies on “dark matter” inclusively by bridging theory, collider experiments, direct detection experiments, and indirect searches (Aug.20th 2019 - )

Dark Matter Working Group website

Objectives

Aim

This working group aims to understand “dark matter” inclusively by bridging theory, collider experiments, direct detection experiments, and indirect searches.

Motivation

The nature of dark matter (DM) has been mystery for a long time. We only know that it occupies about a quarter of the total energy density of the Universe and it must barely interact with baryonic matter, except through the gravity. To unveil its property, three kinds of experiments, collider, direct, and indirect searches are undertaken. However, none of them have found the signature. Among various DM candidates, Weakly Interacting Massive Particle (WIMP) has long been considered as one of the most plausible candidates. For WIMP, of which mass is expected to be in GeV region, direct detection experiments are approaching the so-called neutrino floor (i.e., neutrino and WIMP scattering cannot be distinguished). Indirect searches also constrain the annihilation cross-section of WIMP to be smaller than the canonical value in the same mass region. In this energy region, strong constraints are also imposed by collider experiments. This strongly suggests that we have to reconsider much wider candidates such as axion or primordial black holes, as well as the meaning of existing constraints. In order to derive the inclusive property of DM, it is necessary to combine all the available information from all kinds of experiments with its theoretical implications, which helps us to make future DM hunting strategy. We need more interplay and interdisciplinary discussions in parallel with the progress of specialized researches. We launch this working group to share the concepts/technologies/strategies/understandings of theoretical and all kinds of the experimental searches of dark matter and develop strategies to discover hints for DM properties in the near-future experiments.

Facilitators:
Nagisa Hiroshima (University of Toyama, RIKEN iTHEMS)
Kohei Hayashi (Tohoku University, ICRR)