Search for a massless dark photon in Λ c + → p γ ′ decay

• Published in: Physical review. D 2022-10, Vol.106 (7), Article 072008
• Main Authors: Ablikim, M., Achasov, M. N., Adlarson, P., Albrecht, M., Aliberti, R., Amoroso, A., An, M. R., An, Q., Bai, X. H., Bai, Y., Bakina, O., Baldini Ferroli, R., Balossino, I., Ban, Y., Batozskaya, V., Becker, D., Begzsuren, K., Berger, N., Bertani, M., Bettoni, D., Bianchi, F., Bloms, J., Bortone, A., Boyko, I., Briere, R. A., Brueggemann, A., Cai, H., Cai, X., Calcaterra, A., Cao, G. F., Cao, N., Cetin, S. A., Chang, J. F., Chang, W. L., Chelkov, G., Chen, C., Chen, Chao, Chen, G., Chen, H. S., Chen, M. L., Chen, S. J., Chen, S. M., Chen, T., Chen, X. R., Chen, X. T., Chen, Y. B., Chen, Z. J., Cheng, W. S., Choi, S. K., Chu, X., Cibinetto, G., Cossio, F., Cui, J. J., Dai, H. L., Dai, J. P., Dbeyssi, A., de Boer, R. E., Dedovich, D., Deng, Z. Y., Denig, A., Denysenko, I., Destefanis, M., De Mori, F., Ding, Y., Dong, J., Dong, L. Y., Dong, M. Y., Dong, X., Du, S. X., Egorov, P., Fan, Y. L., Fang, J., Fang, S. S., Fang, W. X., Fang, Y., Farinelli, R., Fava, L., Feldbauer, F., Felici, G., Feng, C. Q., Feng, J. H., Fischer, K., Fritsch, M., Fritzsch, C., Fu, C. D., Gao, H., Gao, Y. N., Gao, Yang, Garbolino, S., Garzia, I., Ge, P. T., Ge, Z. W., Geng, C., Gersabeck, E. M., Gilman, A., Goetzen, K., Gong, L., Gong, W. X., Gradl, W., Greco, M.
• Format: Article
• Language: English
• Subjects: PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
• ISSN: 2470-0010; 2470-0029; 2470-0029
• DOI: 10.1103/PhysRevD.106.072008

A search for a massless dark photon y' is conducted using 4.5 fb-1 of e+⁢e- collision data collected at center-of-mass energies between 4.600 and 4.699 GeV with the BESIII detector at BEPCII. No significant signal is observed, and the upper limit on the branching fraction $\mathscr{B}$⁡(${\Lambda}_c^{+}$ → p⁢y') is determined to be 8.0 × 10-5 at 90% confidence level.