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ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2012, vol. 86, p. -

Study of ψ(3686)→π0h c, h c→γη c via η c exclusive decays

Ablikim M., Achasov M. N., Albayrak O., Ambrose D. J., An F. F., An Q., Bai J. Z., Ban Y., Becker J., Bennett J. V., Bertani M., Bian J. M., Boger E., Bondarenko O., Boyko I., Briere R. A., Bytev V., Cai X., Cakir O., Calcaterra A., Cao G. F., Cetin S. A., Chang J. F., Chelkov G., Chen G., Chen H. S., Chen J. C., Chen M. L., Chen S. J., Chen X., Chen Y. B., Cheng H. P., Chu Y. P., Cronin-Hennessy D., Dai H. L., Dai J. P., Dedovich D., Deng Z. Y., Denig A., Denysenko I., Destefanis M., Ding W. M., Ding Y., Dong L. Y., Dong M. Y., Du S. X., Fang J., Fang S. S., Fava L., Feldbauer F., Feng C. Q., Ferroli R. B., Fu C. D., Fu J. L., Gao Y., Geng C., Goetzen K., Gong W. X., Gradl W., Greco M., Gu M. H., Gu Y. T., Guan Y. H., Guo A. Q., Guo L. B., Guo Y. P., Han Y. L., Harris F. A., He K. L., He M., He Z. Y., Held T., Heng Y. K., Hou Z. L., Hu H. M., Hu T., Huang G. M., Huang G. S., Huang J. S., Huang X. T., Huang Y. P., Hussain T., Ji C. S., Ji Q., Ji Q. P., Ji X. B., Ji X. L., Jiang L. L., Jiang X. S., Jiao J. B., Jiao Z., Jin D. P., Jin S., Jing F. F.

The process ψ(3686)→π0h c, h c→γ η c has been studied with a data sample of 106±4 million ψ(3686) events collected with the BESIII detector at the BEPCII storage ring. The mass and width of the P-wave charmonium spin-singlet state h c(P11) are determined by simultaneously fitting distributions of the π0 recoil mass for 16 exclusive η c decay modes. The results, M(h c)=3525.31±0.11(stat)±0.14(syst)MeV/c2 and Γ(h c)=0.70±0.28±0.22MeV, are consistent with and more precise than previous measurements. We also determine the branching ratios for the 16 exclusive η c decay modes, five of which have not been measured previously. New measurements of the η c line-shape parameters in the E1 transition h c→γη c are made by selecting candidates in the h c signal sample and simultaneously fitting the hadronic mass spectra for the 16 η c decay channels. The resulting η c mass and width values are M(η c)=2984.49±1.16±0.52MeV/c2 and Γ(η c)=36.4±3.2±1.7MeV. © 2012 American Physical Society.