Search for η c ( 2 S ) → p p ¯ and branching fraction measurements of χ c J → p p ¯ via ψ ( 2 S ) radiative decays

• Published in: Physical review. D 2025-01, Vol.111 (1), Article 012003
• Main Authors: Ablikim, M., Achasov, M. N., Adlarson, P., Afedulidis, O., Ai, X. C., Aliberti, R., Amoroso, A., Bai, Y., Bakina, O., Balossino, I., Ban, Y., Bao, H.-R., Batozskaya, V., Begzsuren, K., Berger, N., Berlowski, M., Bertani, M., Bettoni, D., Bianchi, F., Bianco, E., Bortone, A., Boyko, I., Briere, R. A., Brueggemann, A., Cai, H., Cai, X., Calcaterra, A., Cao, G. F., Cao, N., Cetin, S. A., Chai, X. Y., Chang, J. F., Che, G. R., Che, Y. Z., Chelkov, G., Chen, C., Chen, C. H., Chen, Chao, Chen, G., Chen, H. S., Chen, H. Y., Chen, M. L., Chen, S. J., Chen, S. L., Chen, S. M., Chen, T., Chen, X. R., Chen, X. T., Chen, Y. B., Chen, Y. Q., Chen, Z. J., Choi, S. K., Cibinetto, G., Cossio, F., Cui, J. J., Dai, H. L., Dai, J. P., Dbeyssi, A., de Boer, R. E., Dedovich, D., Deng, C. Q., Deng, Z. Y., Denig, A., Denysenko, I., Destefanis, M., De Mori, F., Ding, B., Ding, X. X., Ding, Y., Dong, J., Dong, L. Y., Dong, M. Y., Dong, X., Du, M. C., Du, S. X., Duan, Y. Y., Duan, Z. H., Egorov, P., Fan, G. F., Fan, J. J., Fan, Y. H., Fang, J., Fang, S. S., Fang, W. X., Fang, Y. Q., Farinelli, R., Fava, L., Feldbauer, F., Felici, G., Feng, C. Q., Feng, J. H., Feng, Y. T., Fritsch, M., Fu, C. D., Fu, J. L., Fu, Y. W., Gao, H., Gao, X. B.
• Format: Article
• Language: English
• ISSN: 2470-0010; 2470-0029
• DOI: 10.1103/PhysRevD.111.012003

Using ( 27.12 ± 0.14 ) × 10 8 ψ ( 2 S ) events collected by the BESIII detector operating at BEPCII, we search for the decay η c ( 2 S ) → p p ¯ via the process ψ ( 2 S ) → γ η c ( 2 S ) and only find a signal with a significance of 1.7 σ . The upper limit of the product branching fraction at the 90% confidence level is determined to be B ( ψ ( 2 S ) → γ η c ( 2 S ) ) × B ( η c ( 2 S ) → p p ¯ ) < 2.4 × 10 − 7 . The branching fractions of χ c J → p p ¯ ( J = 0 , 1 , 2 ) are also measured to be B ( χ c 0 → p p ¯ ) = ( 2.51 ± 0.02 ± 0.08 ) × 10 − 4 , B ( χ c 1 → p p ¯ ) = ( 8.16 ± 0.09 ± 0.25 ) × 10 − 4 , and B ( χ c 2 → p p ¯ ) = ( 8.33 ± 0.09 ± 0.22 ) × 10 − 4 , where the first uncertainty is statistical and the second systematic.