Hadronic transitions of $\chi_{ cJ}\to \eta_{ c}\pi^{ +}\pi^{ -}$ (J=0, 1, 2) are searched for using a sample of $1.06\times 10^{ 8}$ $\psi(3686)$ events collected with the BESIII detector at the BEPCII storage ring. The $\etac$ is reconstructed with $K_{ S}^{ 0}K^{ +}\pi^{ -}+c.c.$ and $K^{ +}K^{ -}\pi^{ 0}$ final states. No signals are observed in any of the three $\chi_{ cJ}$ states in either $\etac$ decay mode. At the 90% confidence level, the upper limits are determined to be $\BR(\chi_{ c0}\to \eta_{ c}\pi^{ +}\pi^{ -})<0.07%$, $\BR(\chi_{ c1}\to \eta_{ c}\pi^{ +}\pi^{ -})<0.32%$, and $\BR(\chi_{ c2}\to \eta_{ c}\pi^{ +}\pi^{ -})<0.54%$. The upper limit of $\BR(\chi_{ c1}\to \eta_{ c}\pi^{ +}\pi^{ -}$ is lower than the existing theoretical prediction by almost an order of magnitude. The branching fractions of $\chi_{ cJ}\to K_{ S}^{ 0}K^{ +}\pi^{ -}\pi^{ +}\pi^{ -}+c.c.$, $K^{ +}K^{ -}\pi^{ +}\pi^{ -}\pi^{ 0}$, $\omega K^{ +}K^{ -}$ and $\phi\pi^{ +}\pi^{ -}\pi^{ 0}$ (J=0, 1, 2) are measured for the first time.
Categories: hep-ex