Search for the decay ?c1 (3872) ??+?-?c1

Using a data sample corresponding to an integrated luminosity of 10.9 fb-1 collected at center-of-mass energies from 4.16 to 4.34 GeV with the BESIII detector, we search for the decay ?c1(3872)??+?-?c1 in the radiative production e+e-???c1(3872). No significant signal is observed, and the ratio for the branching fraction of ?c1(3872)??+?-?c1 to ?c1(3872)??+?-J/? is measured as RB[?c1(3872)??+?-?c1]B[?c1(3872)??+?-J/?]<0.18 at 90% confidence level. An upper limit on the product of the cross section ?[e+e-???c1(3872)] and the branching fraction B[?c1(3872)??+?-?c1] at each center-of-mass energy is also given. These measurements favor the nonconventional charmonium nature of the ?c1(3872) state. © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.