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New particle 'discovered at CERN'

Physicists have discovered a new particle composed of three quarks in the Large Hadron Collider (LHC) accelerator in Switzerland, confirming the fundamental assumptions of physics regarding the binding of quarks.
In the course of proton collisions in the LHC at CERN, physicists Claude Amsler, Vincenzo Chiochia and Ernest Aguil from the University of Zurich Physics Institute managed to detect a baryon with one light and two heavy quarks.
The particle Xi_b^* comprises one "up", one "strange" and one "bottom" quark , is electrically neutral and has a spin of 3/2 (1.5). Its mass is comparable to that of a lithium atom.

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Title: Observation of an excited Xi(b) baryon
Authors: CMS Collaboration

The observation of an excited b baryon via its strong decay into Xi(b)^- pi^+ (plus charge conjugates) is reported. The measurement uses a data sample of pp collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 5.3 inverse femtobarns. The known Xi(b)^- baryon is reconstructed via the decay chain Xi(b)^- to J/psi Xi^- to mu^+ mu^- Lambda^0 pi^-, with Lambda^0 to p pi^-. A peak is observed in the distribution of the difference between the mass of the Xi(b)^- pi^+ system and the sum of the masses of the Xi(b)^- and pi^+, with a significance exceeding five standard deviations. The mass difference of the peak is 14.84 0.74 (stat.) 0.28 (syst.) MeV. The new state most likely corresponds to the Xi(b)^{*0} baryon, the J^P=3/2^+ excitation of the Xi(b)^0.

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