@article{9bc05f4d40ac4e118fc6dee83ac0a71a,

title = "Observation of Multiplicity Dependent Prompt χc1 (3872) and ψ (2S) Production in pp Collisions",

abstract = "The production of χc1(3872) and ψ(2S) hadrons is studied as a function of charged particle multiplicity in pp collisions at a center-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 2 fb-1. For both states, the fraction that is produced promptly at the collision vertex is found to decrease as charged particle multiplicity increases. The ratio of χc1(3872) to ψ(2S) cross sections for promptly produced particles is also found to decrease with multiplicity, while no significant dependence on multiplicity is observed for the equivalent ratio of particles produced away from the collision vertex in b-hadron decays. This behavior is consistent with a calculation that models the χc1(3872) structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the χc1(3872) state are discussed.",

author = "{(LHCb Collaboration)} and R. Aaij and {Abell{\'a}n Beteta}, C. and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and Aidala, {C. A.} and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and {Alfonso Albero}, A. and Z. Aliouche and G. Alkhazov and {Alvarez Cartelle}, P. and S. Amato and Y. Amhis and L. An and L. Anderlini and A. Andreianov and M. Andreotti and F. Archilli and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and M. Bachmayer and Back, {J. J.} and S. Baker and {Baladron Rodriguez}, P. and V. Balagura and W. Baldini and {Baptista Leite}, J. and Barlow, {R. J.} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and Basels, {J. M.} and G. Bassi and B. Batsukh and S. Blusk and Rudolph, {M. S.} and T. Skwarnicki and S. Stone",

note = "Publisher Copyright: {\textcopyright} 2021 CERN. ",

year = "2021",

month = mar,

day = "5",

doi = "10.1103/PhysRevLett.126.092001",

language = "English (US)",

volume = "126",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "9",

}