Observation of $e^+e^- \to \gamma \chi_{c1}$ and search for $e^+e^- \to \gamma \chi_{c0}, \gamma \chi_{c2},$ and $\gamma\eta_c$ at $\sqrt{s}$ near 10.6 GeV at Belle
Creators: name: Jia, S.
name: Wang, X. L.
name: Shen, C. P.
name: Yuan, C. Z.
name: Adachi, I.
name: Aihara, H.
name: Al Said, S.
name: Asner, D. M.
name: Atmacan, H.
name: Aulchenko, V.
name: Aushev, T.
name: Ayad, R.
name: Babu, V.
name: Bansal, V.
name: Behera, P.
name: Beleño, C.
name: Berger, M.
name: Bhuyan, B.
name: Bilka, T.
name: Biswal, J.
name: Bobrov, A.
name: Bozek, A.
name: Bračko, M.
name: Browder, T. E.
name: Cao, L.
name: Červenkov, D.
name: Chang, P.
name: Chekelian, V.
name: Chen, A.
name: Cheon, B. G.
name: Chilikin, K.
name: Cho, K.
name: Choi, S.-K.
name: Choi, Y.
name: Choudhury, S.
name: Cinabro, D.
name: Cunliffe, S.
name: Dash, N.
name: Di Carlo, S.
name: Doležal, Z.
name: Dong, T. V.
name: Eidelman, S.
name: Epifanov, D.
name: Fast, J. E.
name: Ferber, T.
name: Frey, A.
name: Fulsom, B. G.
name: Garg, R.
name: Gaur, V.
name: Gabyshev, N.
name: Garmash, A.
name: Gelb, M.
name: Giri, A.
name: Goldenzweig, P.
name: Greenwald, D.
name: Haba, J.
name: Hayasaka, K.
name: Hayashii, H.
name: Hou, W.-S.
name: Hsu, C.-L.
name: Iijima, T.
name: Inami, K.
name: Inguglia, G.
name: Ishikawa, A.
name: Itoh, R.
name: Iwasaki, M.
name: Iwasaki, Y.
name: Jacobs, W. W.
name: Jin, Y.
name: Joffe, D.
name: Kahn, J.
name: Kaliyar, A. B.
name: Karyan, G.
name: Kawasaki, T.
name: Kichimi, H.
name: Kiesling, C.
name: Kim, D. Y.
name: Kim, H. J.
name: Kim, J. B.
name: Kim, S. H.
name: Kinoshita, K.
name: Kodyš, P.
name: Korpar, S.
name: Kotchetkov, D.
name: Križan, P.
name: Kroeger, R.
name: Krokovny, P.
name: Kuhr, T.
name: Kulasiri, R.
name: Kumar, R.
name: Kuzmin, A.
name: Kwon, Y.-J.
name: Lalwani, K.
name: Lange, J. S.
name: Lee, I. S.
name: Lee, J. Y.
name: Lee, S. C.
name: Li, C. H.
name: Li, L. K.
name: Li, Y. B.
name: Li Gioi, L.
name: Libby, J.
name: Liptak, Z.
name: Liventsev, D.
name: Lu, P.-C.
name: Lubej, M.
name: MacNaughton, J.
name: Masuda, M.
name: Matsuda, T.
name: Matvienko, D.
name: Merola, M.
name: Miyata, H.
name: Mizuk, R.
name: Mori, T.
name: Mussa, R.
name: Nakano, E.
name: Nakao, M.
name: Nath, K. J.
name: Nayak, M.
name: Nisar, N. K.
name: Nishida, S.
name: Ogawa, S.
name: Olsen, S. L.
name: Ono, H.
name: Onuki, Y.
name: Ostrowicz, W.
name: Pakhlova, G.
name: Pal, B.
name: Pardi, S.
name: Paul, S.
name: Pedlar, T. K.
name: Pestotnik, R.
name: Piilonen, L. E.
name: Popov, V.
name: Prencipe, E.
name: Ritter, M.
name: Rostomyan, A.
name: Russo, G.
name: Sakai, Y.
name: Salehi, M.
name: Sandilya, S.
name: Santelj, L.
name: Sanuki, T.
name: Savinov, V.
name: Schneider, O.
name: Schnell, G.
name: Schueler, J.
name: Schwanda, C.
name: Seino, Y.
name: Senyo, K.
name: Sevior, M. E.
name: Shibata, T.-A.
name: Shiu, J.-G.
name: Simon, F.
name: Sokolov, A.
name: Solovieva, E.
name: Starič, M.
name: Stottler, Z. S.
name: Strube, J. F.
name: Sumiyoshi, T.
name: Sutcliffe, W.
name: Takizawa, M.
name: Tanida, K.
name: Tao, Y.
name: Tenchini, F.
name: Uchida, M.
name: Uehara, S.
name: Uglov, T.
name: Unno, Y.
name: Uno, S.
name: Urquijo, P.
name: Usov, Y.
name: Van Tonder, R.
name: Varner, G.
name: Varvell, K. E.
name: Vorobyev, V.
name: Waheed, E.
name: Wang, B.
name: Wang, C. H.
name: Wang, M.-Z.
name: Wang, P.
name: Watanuki, S.
name: Widmann, E.
name: Won, E.
name: Yamamoto, H.
name: Yang, S. B.
name: Ye, H.
name: Yin, J. H.
name: Yusa, Y.
name: Zhang, Z. P.
name: Zhilich, V.
name: Zhukova, V.
name: Zhulanov, V.
Publisher: name: Deutsches Elektronen-Synchrotron, DESY, Hamburg
Year: 2018
Subjects: subject: 530
subject: electron positron: annihilation
subject: electron positron: colliding beams
subject: channel cross section: measured
subject: energy dependence
subject: chi/c0(3415)
subject: chi/c1(3510)
subject: chi/c2(3555)
subject: photon: spectrum
subject: BELLE
subject: exclusive reaction
subject: KEK-B
subject: BES
subject: channel cross section: upper limit
subject: Born approximation
subject: tree approximation
subject: experimental results
subject: electron positron --&gt; photon chi/c0(3415)
subject: electron positron --&gt; photon chi/c1(3510)
subject: electron positron --&gt; photon chi/c2(3555)
subject: 10.58 GeV-cms

description: 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 GeV, 10.58 GeV, and 10.867 GeV, respectively, we study the exclusive reactions $e^+e^-\to\gamma\chi_{cJ}$ ($J = 0,~1,~2$) and $e^+e^-\to\gamma\eta_c$. A significant $\gamma \chi_{c1}$ signal is observed for the first time at $\sqrt{s}=10.58$ GeV with a significance of $5.1\sigma$ including systematic uncertainties. No significant excesses for $\gamma \chi_{c0}$, $\gamma \chi_{c2}$, and $\gamma \eta_c$ final states are found, and we set 90\% credibility level upper limits on the Born cross sections ($\sigma_{\rm B}$) 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 $\sigma_{\rm B}(e^+e^-\to\gamma\chi_{c1})$ is obtained.