Observation of structure in the J/ψ-pair mass spectrum
Using proton-proton collision data at centre-of-mass energies of √s = 7; 8 and 13 TeV recorded by the ffiffi LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb , the invariant mass spectrum of J/w pairs is studied. A narrow structure around 6:9 GeV=c mat...
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| Format: | Article |
| Language: | English |
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Elsevier BV
2022
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| Online Access: | https://hdl.handle.net/1721.1/142456 |
| Summary: | Using proton-proton collision data at centre-of-mass energies of √s = 7; 8 and 13 TeV recorded by the ffiffi LHCb experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 9 fb , the invariant mass spectrum of J/w pairs is studied. A narrow structure around 6:9 GeV=c 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 7:4 GeV=c , 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. -1 2 2 |
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