Measurement of eta(c) (1S), eta(c)(2S), and nonresonant eta 'pi(+)pi(-) production via two-photon collisions

作者：Xu, Q. N.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Atmacan, H.; Aulchenko, V.; Aushev, T.; Ayad, R.; Babu, V.; Badhrees, I.; Bakich, A. M.; Bansal, V.; Barberio, E.; Behera, P.; Berger, M.; Bhardwaj, V.; Bhuyan, B.; Biswal, J.; Bondar, A.; Bozek, A.; Bracko, M.; Cervenkov, D.; Chen, A.; Cheon, B. G.; Chilikin, K.; Cho, K.; Choi, S. -K.; Choi, Y.; Cinabro, D.; Cunliffe, S.; Czank, T.; Dash, N.; Di Carlo, S.; Dolezal, Z.; Drasal, Z.; Eidelman, S.; Epifanov, D.; Fast, J. E.; Ferber, T.

来源：PHYSICAL REVIEW D, 2018, 98(7): 072001.

DOI：10.1103/PhysRevD.98.072001

• QUARKONIUM
• DECAYS
• MESONS

We report the measurement of gamma gamma -> eta(c) (1S) -> eta(c) (2S) -> eta'pi(+)pi(-) with eta' decays to gamma rho and eta pi(+)pi(-) using 941 fb(-1) of data collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The eta(c) (1S) mass and width are measured to be M = [2984.6 +/- 0.7 (sta) +/- 2.2 (syst) +/- 0.3 (model)] MeV/c(2) and Gamma = [30.8(-2.2)(+2.3) (stat) +/- 2.5 (syst) +/- 1.4 (model)] MeV, respectively. First observation of eta(c) (2S) -> eta'pi(+)pi(-) with a significance of 5.5 sigma including systematic error is obtained, and the eta(c) (2S)mass is measured to be M = [3635.1 +/- 3.7 (stat) +/- 2.9 (syst) +/- 0.4 (model)] MeV/c(2). The products of the two-photon decay width and branching fraction (B) of decays to eta'pi(+)pi(-) are determined to be Gamma(gamma gamma)Gamma B-gamma gamma = [65.4 +/- 2.6 (stat) +/- 7.

• 出版日期2018-10-3
• 单位北京航空航天大学