Using data samples of 89.5 fb(-1), 711.0 fb(-1), and 121.4 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider at center-of-mass energies 10.52, 10.58, and 10.867 GeV, respectively, we study the exclusive reactions e(+)e(-) -> gamma chi(cJ) (J = 0, 1, 2) and e(+)e(-) -> gamma chi(c). A significant gamma chi(c1) signal is observed for the first time at root s = 10.58 GeV with a significance of 5.1 sigma including systematic uncertainties. No significant excesses for gamma chi(c0), gamma chi(c2), and gamma chi(c) final states are found, and we set 90% credibility level upper limits on the Born cross sections (sigma(B)) at 10.52 GeV, 10.58 GeV, and 10.867 GeV. Together with cross sections measured by BESIII at lower center-of-mass energies, the energy dependency of sigma(B) (e(+)e(-) -> gamma chi(c1)) thorn is obtained.
Lenka Zdeborová, Emanuele Troiani, Giovanni Piccioli
Matthias Finger, Qian Wang, Yiming Li, Varun Sharma, Konstantin Androsov, Jan Steggemann, Xin Chen, Rakesh Chawla, Matteo Galli, Jian Wang, João Miguel das Neves Duarte, Tagir Aushev, Matthias Wolf, Yi Zhang, Tian Cheng, Yixing Chen, Werner Lustermann, Andromachi Tsirou, Alexis Kalogeropoulos, Andrea Rizzi, Ioannis Papadopoulos, Paolo Ronchese, Hua Zhang, Leonardo Cristella, Siyuan Wang, Tao Huang, David Vannerom, Michele Bianco, Sebastiana Gianì, Sun Hee Kim, Davide Di Croce, Kun Shi, Abhisek Datta, Jian Zhao, Federica Legger, Gabriele Grosso, Anna Mascellani, Ji Hyun Kim, Donghyun Kim, Zheng Wang, Sanjeev Kumar, Wei Li, Yong Yang, Ajay Kumar, Ashish Sharma, Georgios Anagnostou, Joao Varela, Csaba Hajdu, Muhammad Ahmad, Ekaterina Kuznetsova, Ioannis Evangelou, Milos Dordevic, Meng Xiao, Sourav Sen, Xiao Wang, Kai Yi, Jing Li, Rajat Gupta, Hui Wang, Seungkyu Ha, Pratyush Das, Anton Petrov, Xin Sun, Valérie Scheurer, Muhammad Ansar Iqbal, Lukas Layer