Discovery Center – Niels Bohr Institute - University of Copenhagen

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Niels Bohr Institute > Research > Particle Physics > Discovery Center

 

Building of the world

What happened in the first few fractions of a second of the life of the universe and what consequences has it had on how the world looks today? There are convincing arguments that the prevailing theory for the smallest particles in the universe, the Standard Model, is not complete.

Atlas detektor at CERNs Large Hadron Collider.

The more presence of the unknown ‘dark matter' everywhere in the universe requires an expansion of the model with previously unknown elementary particles. The enormous detectors at CERN's Large Hadron Collider open up exciting possibilities for finding these new particles and using the very sensitive instruments on ESA's Planck satellite researchers can measure the weak ‘echoes' from the particles in the early universe. 

Break in symmetry

The Standard Model is based on a symmetry that binds the electromagnetic forces (which are responsible the atoms, molecules and chemical processes) together with the weak forces (which are responsible for the radioactive processes, which keep the Sun and the Earth warm). If the symmetry was unbroken, the electromagnetic and weak forces should have almost the same strength, but they clearly do not. In the Standard Model the break in symmetry is caused by an omnipresent "Higgs field", which to a greater or lesser extent hinders the movement of all elementary particles and with that gives them mass. This field should give rise to a "Higgs particle", which has yet been seen. It is a primary objective of the center to find this particle - or another which can replace it. If a Higgs particle exists, entirely new particles must almost inevitably exist and these new particles could simultaneously explain the dark matter in the universe.


The Planck satellite was launched on May 14th, 2009 and is located 1.5 million km away from Earth.

Particle physics and cosmology

In the early universe there were far more photons than atomic nuclei and electrons. When nuclei and electrons combined to form hydrogen atoms around 400,000 years after the Big Bang, these photons were released and can be seen today as the omnipresent cosmic microwave background radiation. It is the very, very small variations in this radiation, which the Planck satellite can measure with unprecedented precision. The variations from place to place in the temperature of the radiation correspond to the change in the average temperature of the Moon that the presence of a living rabbit on the Moon would cause. The small variations, however, contains a wealth of information about the particles that were present in the early universe and in that way are an invaluable bridge between the smallest and largest scales of longitude.
 

Homepage: discoverycenter.dk