CERN Accelerating science

Record fill for CMS: recorded 35.5 pb-1 ("inverse picobarns") of collisions - almost as much as we recorded in the whole of 2010!

The t t-bar production cross section and top quark mass are measured in proton-proton collisions at sqrt(s) = 7 TeV in a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected by the CMS experiment.

The CMS collaboration is presenting its latest results this week at the annual Quark Matter conference, held this year in Annecy, France.

The CMS experiment has made several unique measurements using data from LHC collisions of lead nuclei (PbPb, November 2010) at centre-of-mass energies of 2.76 TeV per nucleon pair.

In our Universe today, quarks are always bound together by gluons to form "composite" particles such as protons and neutrons. The Quark-Gluon Plasma, or QGP, often described as a soup-like medium, is a hot, dense state in which these quarks and gluons exist freely, unbound.

The paper, accepted for publication in Physical Review D in April, presents the first measurement of Υ (Upsilon) production at a centre-of-mass collision energy of 7 TeV at the LHC.