What is dark matter, and does it even exist?
- Particle Physics (IPA)
- Astrophysics (IPA)
Fundamental questions can usually be solved better in cooperation between different disciplines than from a single perspective. Especially when a problem has remained unsolved for decades, despite intensive research: What is dark matter and does it even exist?
What looks at first glance to be a special field of basic research that is not particularly relevant to everyday life, quickly fascinates also laypersons. A well-established model of research puts the known and visible matter in the total energy–matter balance of the universe at 4%. Another 25% consists of dark matter and the remaining 70% of dark energy. According to the currently discussed model, researchers assume that despite the large rotational velocities of visible matter in galaxies, these galaxies do not fly apart because they are held together by the gravitational force of an invisible, not luminescent — and hence 'dark' — matter.
Enormously broad field of research
There is great interest worldwide in taking a step closer to resolving this issue. Today it is not clear whether the model will be confirmed with further research; whether dark matter can be discovered or whether the standard model of the cosmos and its properties should be questioned. In this case, modifications to the laws of gravity might be an alternative explanation, which is currently also discussed. Basic research here is facing an enormously broad field of research that could turn our entire world view upside down.
Combination of particle physics and cosmology
As the early phases of the Universe have been dominated by a soup of elementary particles, and because cosmic rays consist of elementary particles, there is a natural connection between the fields of astrophysics and particle physics. Switzerland is already strong in many of the research fields concerned, such as cosmology, astrophysics, astroparticle physics, dark energy, dark matter, gravitational waves, planetary physics, particle physics at the highest energies as provided by particle accelerators, neutrino physics, low-energy precision experiments etc. For this reason, the organizers at ETH Zurich and the University of Zurich were enthusiastic when the opportunity came to bring the annual international workshop "PPC 2018" on the connection between particle physics and cosmology to Zurich at the end of August 2018. With this workshop, they could organize an well-established meeting in which more than 90 researchers from 18 nations took part. In 2017 the workshop took place in Texas, in 2019 it will be hosted in Cartagena, Colombia.
Findings from new experiments
In addition to the ever-tighter cooperation, new detectors and telescopes with even more sensitive sensors and different measurement strategies will bring new results. For example, dark matter is being searched for in experiments with huge tanks filled with noble gases (xenon, argon) in liquid form. Thanks to these large masses, it might be possible to observe rare collisions of invisible particles with individual atoms of the detector.
International race for new insights
Despite the worldwide competition and a real race for enlightening results, the atmosphere at the workshop "PPC 2018" was distinctly cooperative. Everyone knows that, in addition to patient research, luck is also needed to “put the money” on the right hypothesis. The hope is high that relevant answers can be found to the fundamental questions in the coming 5 to 10 years, such as the search for dark matter.