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31/03/2009
What is matter made of ?
Grid applications in particle and astroparticle physics;
The CMS and IceCube projects
(a collaboration between the VUB, UGent and UA)
Prof S. Tavernier
Launch Flemish Supercomputer Center
March 23, 2009
Our understanding of nature at the microscopic scale is
summarised in the standard model
4 fundamental forces
mass
fundamental particles
All
?
All these particles have a size of less than 10-18 m
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The standard model is extremely successful in describing subatomic
phenomena, however, there are very good reasons to believe this
model is incomplete.
- the standard model does not integrate gravity, and the description
of gravity is incompatible with quantum mechanics.
- there is compelling evidence from astronomical observations that
95% of the mass in the universe is not accounted for. We have no
room for this missing mass in the standard model.
- the masses of the basic particles are unexplained and vary
enormously, from ≈10-2 eV (neutrinos) to 0.27 1012 eV (top quark).
If our "fundamental" particles are made up of other, more
fundamental, constituents, the corresponding level
spacing is very large.
∆E ≈
π(hc)
2a
∆E[GeV ] ≈
100
size[10 −18 m]
If matter has a structure at a dimension of ≈10-19 m , the
level spacing corresponding to this structure must be
≈1 TeV. To "excite" these levels high energy is needed.
From quantum mechanics we know that to probe the structure
of matter at the very small scale we need very high energy
probes.
λ=
h hc 10 −6 m
≈
≈
P E E[eV ]
With light [ E≈1eV] we can "see"the structure of matter down to
10-6m.
To see the structure of matter at a scale of 10-18 m and below
we need probes with an energy of one TeV [= 1012 eV] or above.
These facts are the motivation for building the very
high-energy accelerators such as LHC.
The LHC (Large Hadron Collider) was recently built
near Geneva, and will allow proton-proton collision
at a centre of mass energy of 14 TeV.
We hope to see a glimpse of what is beyond the
standard model.
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Where the protons collide a large number of new particles is produced
proton 7 TeV 7 TeV proton
proton 7 TeV
7 TeV proton
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From this November onwards, proton beams will collide at a rate of
40 106 per second.
One year of CMS operation will result in about 107 GBytes of data.
To analyse these data CERN is setting up a network of ≈ 100'000 PC
processors distributed over the participating institutions.
In addition to computing power for data analysis, there is a need
for a large computer power for data simulation.
All the calculations needed are trivially parallelizable.
Messengers from the cosmos,
The IceCube experiment
From CMS
to
Ice cube
The Earth is permanently bombarded by very high energy
particles from the cosmos. The energy can be up to 2020eV!
Among these, neutrinos are of particular interest because
they are not affected by intergalactic dust, intergalactic
magnetic field etc.
The ice cube experiment aims at observing high-energy
neutrinos from the cosmos.
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One year of IceCube operation will result in about
104 GBytes of data sent by satellite to the participating
laboratories for analysis.
The analysis of these date needs similar computer
infrastructure as the analysis of the CMS data.
Experiments like CMS and IceCube aim at answering
some of the most fundamental questions in science.
The Flemish universities obviously should take part
in these scientific adventures.
The Flemish Supercomputer Center will help us in
doing so.
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