Aug 28, 2008
The ground state of bottomonium.


η b is the name of the particle recently discovered by the physicists working on the BaBar experiment.This ground state of ‘bottomonium’, a collection of particles formed from a bottom quark and an anti-bottom quark, has been sought for over thirty years. It has now been identified in the disintegration products of the Y(3S) particle, an excited state of bottomonium, using the latest data taken in 2008 by the BaBar experiment.An accurate measurement of the characteristics of this new particle is a determining factor in the testing and determination of the parameters of the theoretical models of the strong interaction.
Apr 18, 2008
Lorentz symmetry probed in the BaBar experiment

The BaBar experiment running on the PEP-II accelerator at SLAC (California) has been collecting data for ten years and has recorded sufficient events to probe the most subtle aspects of the Standard Model of particle physics and quantum field theory. By analysing the behaviour over time of the B-meson particle-antiparticle pairs produced in abundance, a team of researchers including participants from IRFU/SPP has been able to demonstrate that the Universe has no preferred direction, and therefore that Lorentz symmetry, touchstone of modern physics, still holds. This original work is similar in concept to the famous Michelson-Morley experiment that demonstrated the symmetry of the speed of light.

Nov 03, 2008

The 11.75 tonne whole body Iseult magnet to be installed in the Neurospin centre in 2012 will push back the boundaries of cerebral imaging. A key step in the success of this Franco-German project is the development of the SEHT test station in which a nominal field strength of 8 teslas was successfully achieved in early October 2008


Jun 09, 2008
Searching cosmic neutrinos

The last two lines of the ANTARES detector were connected and powered at a depth of 2500 m on the Mediterranean seabed during the night of May 30, 2008. This brings the number of lines to twelve and completes the construction phase of the largest underwater neutrino telescope ever built.
The lines were immersed a few weeks earlier, close to the other lines that have been tracking cosmic neutrinos since 2006. These particles may be able to tell us more about the most violent phenomena in the Universe.
The event rewards the efforts of the European ANTARES collaboration1 and, more especially, of CEA-IRFU, which has been a major contributor to the project.

Dec 15, 2008
In collaboration with IRFU teams, CMS teams are currently making preparations for the first LHC data acquisition campaign.

On November 14, 2008, the Compact Muon Solenoid (CMS) successfully generated a nominal magnetic field of 4 tesla. This success rewards IRFU efforts for the design and construction of what constitutes the largest superconducting solenoid magnet in the world. Over a period of approximately one month, CMS teams conducted a continuous data acquisition campaign with the detector operating under nominal conditions. Approximately 300 million cosmic events were recorded. This also provided an excellent opportunity to showcase the specific expertise of IRFU teams, particularly in areas such as detection systems, electronics, trace data reconstruction techniques and laser control systems.

Aug 04, 2008

Scientists from the CDF and DZero collaborations at the U.S. Department of Energy's Fermilab have combined Tevatron data from the two experiments to advance the quest for the long-sought Higgs boson. They have presented their results on August 3rd at the International Conference on High Energy  Physics in Philadelphia indicating that they have for the first time excluded, with 95 percent probability, a mass for the Higgs  of 170 GeV (about 170 proton masses). This value lies near the middle of the possible mass range for the particle established by earlier experiments. This result not only restricts the possible masses where the Higgs might lie, but it also demonstrates that the Tevatron experiments are sensitive to potential Higgs signals.



Retour en haut