Search for the decay χc1 (3872) →π+π-χc1

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 χc1(3872)→π+π-χc1 in the radiative production e+e-→γχc1(3872). No significant signal is observed, and the ratio for the branching fraction of χc1(3872)→π+π-χc1 to χc1(3872)→π+π-J/ψ is measured as RB[χc1(3872)→π+π-χc1]B[χc1(3872)→π+π-J/ψ]<0.18 at 90% confidence level. An upper limit on the product of the cross section σ[e+e-→γχc1(3872)] and the branching fraction B[χc1(3872)→π+π-χc1] at each center-of-mass energy is also given. These measurements favor the nonconventional charmonium nature of the χc1(3872) state.