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.

Язык оригиналаанглийский
Страницы (с-по)1983-1993
Число страниц11
ЖурналScience Bulletin
Номер выпуска23
СостояниеОпубликовано - 15 дек 2020


Подробные сведения о темах исследования «Observation of structure in the J/ψ-pair mass spectrum». Вместе они формируют уникальный семантический отпечаток (fingerprint).