@article{56a0fce1bc6842ff943e6ad12cf2116f,

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

abstract = "The production of chi(c1)(3872) and psi(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 chi(c1) (3872) to psi(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 chi(c1) (3872) structure as a compact tetraquark. Comparisons with model calculations and implications for the binding energy of the chi(c1)(3872) state are discussed.",

author = "R. Aaij and C.A. Beteta and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and C.A. Aidala and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and A.A. Albero and Z. Aliouche and G. Alkhazov and P.A. Cartelle 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 J.J. Back and S. Baker and P.B. Rodriguez and V. Balagura and W. Baldini and J.B. Leite and R.J. Barlow and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and J.M. Basels and G. Bassi and B. Batsukh and A. Battig and A. Bay and M. Becker and F. Bedeschi and {LHCb collaboration} and {de Vries}, J.A. and M.H.M. Merk",

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

year = "2021",

month = mar,

day = "5",

doi = "10.1103/PhysRevLett.126.092001",

language = "English",

volume = "126",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "9",

}