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-1, the invariant mass spectrum of J/w pairs is studied. A narrow structure around 6:9 GeV=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 7:4 GeV=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.

Aaij, R., Abellan Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., et al. (2020). Observation of structure in the J/ψ-pair mass spectrum. SCIENCE BULLETIN, 65(23), 1983-1993 [10.1016/j.scib.2020.08.032].

Observation of structure in the J/ψ-pair mass spectrum

Borsato M.;Calvi M.;Capelli S.;Carniti P.;Fazzini D.;Garcia Pardinas J.;Gotti C.;Martinazzoli L.;Martinelli M.;Meloni S.;Petruzzo M.;Shields E. B.;
2020

Abstract

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-1, the invariant mass spectrum of J/w pairs is studied. A narrow structure around 6:9 GeV=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 7:4 GeV=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.
Articolo in rivista - Articolo scientifico
Exotics; Particle and resonance production; QCD; Quarkonium; Spectroscopy; Tetraquark
English
2020
65
23
1983
1993
none
Aaij, R., Abellan Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., et al. (2020). Observation of structure in the J/ψ-pair mass spectrum. SCIENCE BULLETIN, 65(23), 1983-1993 [10.1016/j.scib.2020.08.032].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/306634
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