New particles found as CERN make data publicly available

CERN has announced that the LHCb experiment at the Large Hadron Collider (LHC) has found two new particles in the baryon family. The organisation – celebrating its 60th anniversary – has also launched its Open Data Portal, making real collision events from LHC experiments available to all. The new particles - Xi_b^’- and Xi_b^*- - are baryons and consist of three quarks bound together by the strong force. However, the types of quarks are different; they both contain one beauty (b), one strange (s) and one down (d) quark. They are more than six times as massive as the proton thanks to their heavyweight b quarks. The mass also depends on their configuration i.e. their spin. In the Xi_b^'- state, the spins of the two lighter quarks point in the opposite direction to the b quark; in the Xi_b^*- state they are aligned. “Nature was kind and gave us two particles for the price of one," said Matthew Charles of the CNRS's LPNHE laboratory at Paris VI University. "The Xi_b^'- is very close in mass to the sum of its decay products: if it had been just a little lighter, we wouldn't have seen it at all using the decay signature that we were looking for.” "This is a very exciting result. Thanks to LHCb's excellent hadron identification, which is unique among the LHC experiments, we were able to separate a very clean and strong signal from the background," said Steven Blusk from Syracuse University. “It demonstrates once again the sensitivity and how precise the LHCb detector is.” The team also studied the particles’ relative production rates, their widths – a measure of how unstable they are – and other details of their decays. The results match predictions based on the theory of Quantum Chromodynamics (QCD), part of the Standard Model of particle physics. The LHCb collaboration has submitted a paper to Physical Review Letters based on these measurements, which were made with data taken during 2011-2012. Data such as this will now be made available on the Open Data Portal. It is expected that this will be of high value for the research community, and also be used for education purposes. "Launching the CERN Open Data Portal is an important step for our Organization,” said CERN Director-General Rolf Heuer. “Data from the LHC programme are among the most precious assets of the LHC experiments, that today we start sharing openly with the world. We hope these open data will support and inspire the global research community, including students and citizen scientists." The Open Data Portal can be found at: http://opendata.cern.ch/ Observation of two new ??b baryon resonances