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Purdue Physicists part of LHC team that has observed hints of melting of Upsilon particles in lead-nuclei collisions

05/23/2011

*Update - July 2011*

The work referenced in this story was published on July 28 2011 in Physical Review letters. It was subsequently designated an "Editor's suggestion" and selected for a Synopsis.

 

In the universe today, quarks are bound together by gluons to form composite particles such as protons and neutrons. The Quark Gluon Plasma (QGP) is a hot dense state in which quarks and gluons move freely, unbound. The universe is believed to have existed as a QGP a few millionths of a second after the Big Bang. Now using data produced by the Large Hadron Collider (LHC) at CERN, the European Laboratory for Particle Physics, in Geneva Switzerland and collected with the the CMS experiment, physicists from Purdue, Fermilab, UCLA, MIT and Ecole Polytechnique in France, have found a deficit of Upsilon particles (Upsilons are subatomic particles containing a beauty quark and an anti-beauty quark in orbit about each other) when lead nuclei collide at the LHC which is indicative of the role played by the QGP in suppressing their production. This suppression has been sought for many years as it is regarded by many as a smoking gun signature for the QGP. Purdue physicists Dr. Nuno Leonardo, Dr. Marco de Mattia, graduate students Zhen Hu and Yu Zheng, and Professor Ian Shipsey formed part of the team that analyzed the data.

 

Read more about the suppression of upsilons here.