Physicists of Fermilab’s CDF and DZero teams have presented statistically significant evidence of the detection of single top quarks in the Tevatron proton/antiproton collider. Physicists used Fermilab’s Tevatron accelerator to discover the top quark in 1995. This quark was the last to be discovered of those predicted to exist by the standard model of quantum mechanics and had only ever been observed in pairs.
The DZero and CDF teams used two different methods to analyze data from trillions of collision events produced by the Tevatron, which is currently operating at an energy of around 1.96 TeV, or 1,960 billion electron volts per accelerated particle. The statistical methods employed in this discovery will be very useful for future data analysis in the search for the Higgs boson, both in the Tevatron and the Large Hadron Collider at CERN.
The LHC has been shut down until at least October for repairs following the explosive release of helium from its cooling system. The explosion took place due to a faulty superconducting magnet, and it destroyed a lot of equipment when it took place last fall. So, the Tevatron remains the highest energy particle accelerator in operation and has a very good chance of finding the Higgs before the LHC.
A research team led by Laurent Gaudefroy of France’s Atomic Energy Commission has demonstrated that the nucleus of an isotope of sulfur, S-43, behaves in a very strange manner. S-43 is unstable and decays after 280 ms. Using gamma ray and magnetic measurements, these scientists found that the S-43 nucleus fluctuates between a spherical and a football-like shape. The spherical shape has a higher energy. This is an unexpected result from the interaction of 16 protons and 27 neutrons in the S-43 nucleus and could greatly affect our understanding of the strong force.
A team of scientists at the University of Warwick and University of Exeter in Britain and Universidade Federal de Sao Carlos in Brazil led by Rudolf Roemer and Andrea Fischer recently published a paper in Physical Review Letters regarding a theoretical model to use a byproduct of the production of quantum dots to controllably ‘freeze’ and release light. A certain method of producing quantum dots sometimes results in ring structures instead of dots called Aharonov-Bohm Rings.
These scientists describe a method of using these ring structures and an electric field to capture photons and store them for any length of time as excitons, which can be triggered to collapse and re-release the photons whenever desired by changing the electric field. An exciton is a bound quantum state in which an electron is excited to a higher energy by a photon and leaves a positive hole in an electric field. When the electron falls back into this hole it emits a photon.
This mechanism would allow for nanomaterials that would be capable of storing and re-emitting light in a controllable way. This is a major step in the direction of creating light-based computers, promising much faster speeds than current electronic computers.
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