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Observation of structure in the J/ψ-pair mass spectrum
Science Bulletin. 2020. Vol. 65. No. 23. P. 1983-1993.
Aaij R., Beteta C. A., Boldyrev A., Derkach D., Hushchyn M., Kazeev N., Maevskiy A., Ratnikov F., Ryzhikov A., Ustyuzhanin A.
Using proton-proton collision data at centre-of-mass energies of s=7,8 and 13TeV recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9fb-1, the invariant mass spectrum of J/ψ pairs is studied. A narrow structure around 6.9GeV/c2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed. The deviation of the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region between 6.2 and 7.4GeV/c2, covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow X(6900) structure are measured assuming a Breit–Wigner lineshape.
Priority areas:
IT and mathematics
Language:
English
Publication based on the results of:
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Пенза : ПГУ, 2016
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