Page 3 of 9 Original Aspects
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LHC (Large Hadron Collider) at CERN (Geneva) is a major international project that
will become reality in a few months with the very first collisions and data
taking. The raison d'être of such a
machine is to understand the mechanism of symmetry breaking, to unravel the
nature of the vacuum and to probe into the mystery of dark matter, DM, by
revealing its microscopic properties.
Although the LHC research program has traditionally centred around the
discovery of the Higgs, it has since been clear that the standard description
of this particle calls for models of New Physics. Until a few years ago the epitome of this New Physics has been supersymmetry
which when endowed with a discrete symmetry furnishes a good dark matter
candidate. Recently a few alternative scenarios have been put forward,
originally also to solve the Higgs problem but it has been discovered that,
generically, their most successful and viable implementation (in accord with
electroweak precision data, proton decay) fares far better if a discrete
symmetry is embedded. This symmetry is also behind the existence of a possible
dark matter candidate. From another
viewpoint, the last few years have witnessed spectacular advances in cosmology
and astrophysics confirming that ordinary matter is a minute part of what
constitutes the Universe at large. At
the same time that the LHC will be gathering data, a host of non-collider
experiments will be carried out in search of DM (AMS, GLAST,HESS, PAMELA, SuperCDMS,
Edelweiss,..) or for the determination of the cosmological parameters, with
unprecedented level of accuracy, making cosmology enter the era of precision,
almost akin of the LEP legacy.
It is high time that our community, at large, grasped and exploited the
new opportunities offered by this new paradigm[1]. This will only be possible if a strong
cross-border collaboration between astrophysicists and collider physicists,
both theorists and experimentalists, comes together and has at its disposal common
and complementary precision tools for the analysis of the forthcoming data. The
stakes are high. For example, if future colliders discover supersymmetric
particles and probe their properties, one could predict the dark matter density
of the Universe and would constrain cosmology with the help of precision data
provided by WMAP and PLANCK[1]. It would
be highly exciting if the precision reconstruction of the relic density from
observables at the colliders does not match PLANCK's determination, this would
mean that the post-inflation era is most
probably not entirely radiation dominated[2]. One can also think of many
situations where the same collider data
on the microscopic properties of DM when put against a combination of data from
direct and indirect detection can give strong constraints on the astrophysical
properties of DM such as its space and velocity distribution as well as clustering (clumps,..), that may reveal much about galaxy
formation[3]. One can also take another
perspective. Imagine a situation like what might occur at the LHC with some new
particles having been discovered but one is unable to determine the mass of the
neutral stable dark matter candidate. An extraction of this mass from a direct
detection experiment (from the nuclear recoil energy), backed up perhaps by a
fit to the indirect detection experiments, even after allowing for
astrophysical uncertainties, can greatly help in further constraining the
particle physics model or discriminating between different models. This will
directly impact on the phenomenology at the LHC while strengthening and
reshaping the strategy for the future e+e- International Linear Collider, ILC. The core of our project is at the heart
of these important issues. These are the kind of global analyses that our team wants
to perform within this project once, and while, the needed cross-border tools
have been, or are, being developed.
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