Observation of the _{b1}(3P) and _{b2}(3P) and Measurement of their Masses. Academic Article uri icon


  • The _{b1}(3P) and _{b2}(3P) states are observed through their (3S) decays, using an event sample of proton-proton collisions collected by the CMS experiment at the CERN LHC. The data were collected at a center-of-mass energy of 13TeV and correspond to an integrated luminosity of 80.0fb^{-1}. The (3S) mesons are identified through their dimuon decay channel, while the low-energy photons are detected after converting to e^{+}e^{-} pairs in the silicon tracker, leading to a _{b}(3P) mass resolution of 2.2MeV. This is the first time that the J=1 and 2 states are well resolved and their masses individually measured: 10513.420.41(stat)0.18(syst)MeV and 10524.020.57(stat)0.18(syst)MeV; they are determined with respect to the world-average value of the (3S) mass, which has an uncertainty of 0.5MeV. The mass splitting is measured to be 10.600.64(stat)0.17(syst)MeV.

published proceedings

  • Phys Rev Lett

author list (cited authors)

  • Sirunyan, A. M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., ... CMS Collaboration.

publication date

  • January 1, 2018 11:11 AM