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Committee for collaboration of Czech Republic

with Joint Institute for Nuclear Research in Dubna Login
Observation of the chi(b1)(3P) and chi(b2)(3P) and Measurement of their Masses

Author
Sirunyan A.M. Yerevan Physics Institute, Armenia
Finger Miroslav, prof. Ing. DrSc. Faculty of Mathematics and Physics, Charles University in Prague
Finger Michael, M.Sc. CSc. Faculty of Mathematics and Physics, Charles University in Prague, JINR Dubna
et al.  CMS collaboration

Year
2018

Scientific journal
Physical Review Letters, 121 (9), 092002

Web


Abstract
The chi(b1)(3P) and chi(b2)(3P) states are observed through their gamma(3S)(gamma) 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 13 TeV and correspond to an integrated luminosity of 80.0 fb(-1). The gamma(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 chi(b)(3P) mass resolution of 2.2 MeV. This is the first time that the J = 1 and 2 states are well resolved and their masses individually measured: 10513.42 +/- 0.41(stat) +/- 0.18(syst) MeV and 10524.02 +/- 0.57(stat) +/- 0.18(syst) MeV; they are determined with respect to the world-average value of gamma(3S) mass, which has an uncertainty of 0.5 MeV. The mass splitting is measured to be 10.60 +/- 0.64(stat) +/- 0.17(syst) MeV.

Cite article as:
A. Sirunyan, M. Finger, M. Finger, . et al., "Observation of the chi(b1)(3P) and chi(b2)(3P) and Measurement of their Masses", Physical Review Letters, 121 (9), 092002 (2018)