Improved measurement of the strong-phase difference δDKπ in quantum-correlated DD¯ decays

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2022-11, Vol.82 (11), p.1009
• Main Authors: Achasov, M. N., An, Q., Bakina, O., Balossino, I., Bianchi, F., Boyko, I., Cai, H., Chang, J. F., Cossio, F., Dbeyssi, A., De Mori, F., Dong, X., Farinelli, R., Feng, C. Q., Feng, J. H., Gu, L. M., He, K. K., Herold, C., Hou, Z. L., Hu, Y., Huang, G. S., Huang, Z., Hussain, T., Janchiv, S., Jang, E., Ji, Q. P., Jiang, H. B., Keshk, I. K., Kiuchi, R., Koch, L., Kolcu, O. B., Kuessner, M., Lange, J. S., Larin, P., Lavania, A., Li, D. M., Li, H., Li, H. B., Li, J. Q., Li, J. W., Libby, J., Liu, C. X., Liu, H., Liu, Huihui, Liu, P. L., Liu, W. M., Liu, Z. Q., Lu, X. L., Lu, Y., Lyu, Y. F., Ma, R. T., Maldaner, S., Mo, X. H., Nikolaev, I. B., Olsen, S. L., Ouyang, Q., Pacetti, S., Pathak, A., Ping, R. G., Qi, M., Qian, W. B., Qin, J. J., Qiu, J. F., Sang, H. S., Shen, H. F., Song, J. J., Song, Y. X., Stieler, F., Sun, G. X., Sun, Z. T., Tan, Y. H., Tan, Y. X., Tat, M., Teng, J. X., Wang, B., Wang, M., Wang, T., Wei, D. H., Wu, L. H., Xiao, H., Xiao, Y. L., Yang, L., Yang, Y. X., Yu, C. X., Yuan, S. C., Zeng, Y., Zhan, Y. H., Zhang, B. X., Zhang, J. X., Zhang, J. Y., Zhang, Jianyu, Zhang, Lei, Zhang, Q. Y., Zhang, X. Y., Zheng, J. P., Zhong, C., Zhou, H., Zhu, J., Zhu, S. H., Zou, B. S.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Asymmetry; Decay; Eigenvectors; Elementary Particles; Fractions; Hadrons; Heavy Ions; Luminosity; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Phase shift; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Rapid prototyping; Regular Article - Experimental Physics; Sensitivity analysis; String Theory; Tags; Uncertainty
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-022-10872-2

The decay D → K - π + is studied in a sample of quantum-correlated D D ¯ pairs, based on a data set corresponding to an integrated luminosity of 2.93 fb - 1 collected at the ψ ( 3770 ) resonance by the BESIII experiment. The asymmetry between C P -odd and C P -even eigenstate decays into K - π + is determined to be A K π = 0.132 ± 0.011 ± 0.007 , where the first uncertainty is statistical and the second is systematic. This measurement is an update of an earlier study exploiting additional tagging modes, including several decay modes involving a K L 0 meson. The branching fractions of the K L 0 modes are determined as input to the analysis in a manner that is independent of any strong phase uncertainty. Using the predominantly C P -even tag D → π + π - π 0 and the ensemble of C P -odd eigenstate tags, the observable A K π π π π 0 is measured to be 0.130 ± 0.012 ± 0.008 . The two asymmetries are sensitive to r D K π cos δ D K π , where r D K π and δ D K π are the ratio of amplitudes and phase difference, respectively, between the doubly Cabibbo-suppressed and Cabibbo-favoured decays. In addition, events containing D → K - π + tagged by D → K S , L 0 π + π - are studied in bins of phase space of the three-body decays. This analysis has sensitivity to both r D K π cos δ D K π and r D K π sin δ D K π . A fit to A K π , A K π π π π 0 and the phase-space distribution of the D → K S , L 0 π + π - tags yields δ D K π = 187.6 - 9.7 + 8.9 - 6.4 + 5.4 ∘ , where external constraints are applied for r D K π and other relevant parameters. This is the most precise measurement of δ D K π in quantum-correlated D D ¯ decays.