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Committee for collaboration of Czech Republic

with Joint Institute for Nuclear Research in Dubna Login
Observation of Two Excited B-c(+) States and Measurement of the B-c(+) (2S) Mass in pp Collisions at root s=13 TeV

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
Afanasyev L.G. JINR
et al.  different institutions

Year
2019

Scientific journal
PHYSICAL REVIEW LETTERS 122 (13) 132001

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Abstract
Signals consistent with the B-c(+)(2S) and B-c*(+)(2S) states are observed in proton-proton collisions at root s = 13 TeV, in an event sample corresponding to an integrated luminosity of 143 fb(-1), collected by the CMS experiment during the 2015-2018 LHC running periods. These excited (b) over barc states are observed in the B-c(+)pi(+)pi(-) invariant mass spectrum, with the ground state B-c(+) reconstructed through its decay to J/psi pi(+). The two states are reconstructed as two well-resolved peaks, separated in mass by 29.1 +/- 1.5(stat) +/- 0.7(syst) MeV. The observation of two peaks, rather than one, is established with a significance exceeding five standard deviations. The mass of the B-c(+)(2S) meson is measured to be 6871.0 +/- 1.2(stat) +/- 0.8(syst) +/- 0.8(B-c(+)) MeV, where the last term corresponds to the uncertainty in the world-average B-c(+) mass.

Cite article as:
A. Sirunyan, M. Finger, M. Finger, L. Afanasyev, . et al., "Observation of Two Excited B-c(+) States and Measurement of the B-c(+) (2S) Mass in pp Collisions at root s=13 TeV ", PHYSICAL REVIEW LETTERS 122 (13) 132001 (2019)