Paper

Precise measurement of the CKM angle \\(\\) with a novel approach

Li, D M, Ghorbanimoghaddam, Z, Battista, P B, Xiang, Z, Xu, Q N, Hu, J F, Xu, Q J, D Vico Benet, Che, G R, Shen, C P, Marangotto, D, Mathad, A, Santoro, L, Strekalina, D, Gys, T, Vecchi, S, Luo, J R, Luo, J S, Dzyuba, A, Pappalardo, L L, Kushnir, V, Pagare, B, Friday, D A, Gao, Y N, Wei, H R, Kaminaris, D, E van Herwijnen, Tisserand, V, Mulder, M, Libby, J, Wislicki, W, Punzi, G, Hennequin, A M, Tao, L Y, Zeng, F R, Jakoubek, T, Perret, P, Gao, Xu, Ma, Q M, Couturier, B, Gao, Y Y, Needham, M, T Hu, Schelhaas, Y, Wang, Shun, Pilato, R N, Wang, Zhi, Korchin, A, Jia, L K, Prouve, C, Wotton, S A, White, C, Spedicato, E, Gilman, A L, Nefedov, Y, Tang, G Y, Schmitz, H, Batozskaya, V, Govorkova, E, Houston, D C, Keizer, F, Elashri, M, Mitreska, B, Lee, H, Wang, X F, Riehn, F, Wang, X L, Wang, X N, Yin, H, Calefice, L, Wang, X W, Swientek, K, Khachatryan, V, Thomson-Strong, A R, Malik, Q A, Zhang, Z D, Fantechi, R, Galati, G, Abdelmotteleb, A S W, Dai, J P, Shao, M, Bottalico, E, Kvapil, J, Johnson, D, Biesuz, N V, Zhang, Shulei, Yan, X Q, Comerma-Montells, A, Luppi, E, Neri, N, You, Z Y, Yin, X, Minotti, A, Chang, H, Hemmer, F, M Senghi Soares, Muhammad, E, Zhang, Z Y, Li, Q M, T Li

2026

Overview

A measurement of the CKM angle \\(\\) is performed by applying a novel, unbinned, model-independent approach to datasets of electron-positron collisions collected by the BESIII experiment and proton-proton collisions by the LHCb experiment, corresponding to integrated luminosities of 8 fb\\(^-1\\) and 9 fb\\(^-1\\), respectively. The \\(C\\!P\\)-violating phase \\(\\) is determined from \\(B^ D( K_ S^0 h^+h^-) h^\\) decays in LHCb data, where \\(h^()\\) is either a pion or kaon, while the corresponding strong-phase parameters are measured using doubly tagged \\(D K_ S/L^0 h^+ h^-\\) decays in the quantum-correlated \\(DD\\) system present in BESIII data. A joint fit to both datasets, which allows for a simultaneous determination of the associated \\(C\\!P\\)-violating observables and strong-phase parameters, yields \\( = (71.3 5.0)^\\). The result is the most precise to date and consistent with previous measurements and world averages.

• Publisher: Cornell University Library, arXiv.org
• Subject: Collisions / Datasets / Kaons / Large Hadron Collider / Parameters / Pions / Protons