A high-resolution version for printing - CP3-Origins

Sustainability is the key for success, and this is why we will provide several permanent positions
in particle physics. This demonstrates strong commitment to the field in Denmark. Several
young researchers and graduate students will have the opportunity of receiving a highly
qualified training while being themselves fundamental
component of the centre's scientific life.
The convergence of its near to perfect timing, outstanding
team, and unprecedented support at the University of
Southern Denmark (SDU) means that CP³-Origins is
acutely primed to raise Danish research to the very top of
the international field of particle physics.
The Need to Go Beyond
The energy scale at which the LHC experiment will operate is
determined by the need to complete the standard model (SM) of particle interactions and, in
particular, to understand the origin of mass of the elementary particles. Together with classical
general relativity the SM constitutes one of the most successful models of nature. We shall,
however, argue that experimental results and theoretical arguments call for a more fundamental
description of nature. The SM can be viewed as a low-energy effective theory valid up to an energy
scale Λ. Above this scale new interactions, symmetries, extra dimensional worlds or any
other extension could emerge. At sufficiently low energies with respect to this scale one expresses
the existence of new physics via effective operators. The success of the SM is due to the
fact that most of the corrections to its physical observables depend only logarithmically on this
scale. In fact, in the SM there exists only one operator which acquires corrections quadratic in Λ.
This is the squared mass operator of the Higgs boson. Since Λ is expected to be the highest possible
scale, which in four dimensions corresponds to the Planck scale, it is hard to explain naturally
why the mass of the Higgs is of the order of the electroweak scale. This is the hierarchy
problem. Due to the occurrence of quadratic corrections in the cutoff scale Λ this SM sector is
most sensitive to the existence of new physics. Many questions need an answer even if the
Higgs is found at the LHC: Is it composite? How many Higgs fields are there in nature? Are
there hidden sectors?
Nature’s Riddles
Why do we expect that there is new physics awaiting to be discovered? Of course, we still have
to observe the Higgs boson. However, even with the Higgs discovered, the SM has both conceptual
problems and phenomenological shortcomings. In fact, theoretical arguments indicate that
the SM is not the ultimate description of nature:
Hierarchy Problem: The Higgs sector is highly fine-tuned. We have no natural separation between
the Planck and the electroweak scale.
Strong CP Problem: There is no natural explanation for the smallness of the electric dipole moment
of the neutron within the SM. This problem is also known as the strong CP problem.
Origin of Patterns: The SM can fit, but cannot explain the number of matter generations and their
mass texture.
CP³-Black book 2