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Of the many ideas for new physics that can be tested at the Large Hadron Collider (LHC), supersymmetry is one of the most promising. The theory proposes that each fundamental fermion particle has a heavier bosonic superpartner (and vice versa for each fundamental boson) and by doing so, offers an extension of the standard model of particle physics that fixes many of its problems. None of the known particles appear to be superpartners, however, which leads to the daunting conclusion that if supersymmetry is correct, there are more than twice as many fundamental particles as we thought, but we have only been left with the lightest partners; that is, supersymmetry is broken.

Good article, though it still doesn't identify dark matter. Could it be the neutralino? Wait the results from the LHC in 2010 with great interest.

For several decades, astronomers and cosmologists have been piling up data that indicates most of the matter in the Universe is dark, interacting only via gravity. As modified theories of gravity failed to account for observation, candidates for dark mater were winnowed down until one remained in favor: the weakly interactive massive particle, or WIMP. Over the past several years, potential signals of WIMPs have appeared in space and on Earth; that, combined with the startup of the LHC, has given the research community the sense that it's close to pinning down the identity of the WIMPs. But a review in this week's Nature considers what might happen if we fail.

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the origin of mass, extra dimensions of space, unification of fundamental forces, and evidence for dark matter candidates in the Universe.

The spacetime symmetries we discussed in the previous post can be expanded to include three discrete symmetries: parity, charge conjugation, and time-reversal. It turns out (rather surprisingly) that physics chooses not to obey these symmetries, and this act of rebellion allowed the universe to develop interesting things like galaxies and life.

One of the reasons why physicists often wax poetic about the beauty of physics is that so much of the field has based on symmetry, and humans find symmetry beautiful.

The predicted neutralino may actually make up a portion or all of dark matter, if it's existence can be proved by the LHC.