Crucial inputs for a variety of CP-violation studies can be determined through the analysis of pairs of quantum-entangled neutral D mesons, which are produced in the decay of the ψ(3770) resonance. The relative strong-phase parameters between D0 and D¯0 in the decays D0→KS,L0π+π- are studied using 2.93 fb-1 of e+e- annihilation data delivered by the BEPCII collider and collected by the BESIII detector at a center-of-mass energy of 3.773 GeV. Results are presented in regions of the phase space of the decay. These are the most precise measurements to date of the strong-phase parameters in D→KS,L0π+π- decays. Using these parameters, the associated uncertainty on the Cabibbo-Kobayashi-Maskawa angle γ/φ3 is expected to be between 0.7° and 1.2° for an analysis using the decay B±→DK±, D→KS0π+π-, where D represents a superposition of D0 and D¯0 states. This is a factor of 3 smaller than that achievable with previous measurements. Furthermore, these results provide valuable input for charm-mixing studies, other measurements of CP violation, and the measurement of strong-phase parameters for other D-decay modes.
Bibliographical noteFunding Information:
The BESIII Collaboration thanks the staff of BEPCII and the IHEP computing center for their strong support. This work is supported in part by National Key Basic Research Program of China under Contract No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts No. 11625523, No. 11635010, No. 11735014, No. 11775027, No. 11822506, and No. 11835012; the Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. U1532257, No. U1532258, No. U1732263, and No. U1832207; CAS Key Research Program of Frontier Sciences under Contracts No. QYZDJ-SSW-SLH003 and No. QYZDJ-SSW-SLH040; 100 Talents Program of CAS; INPAC and Shanghai Key Laboratory for Particle Physics and Cosmology; ERC under Contract No. 758462; German Research Foundation DFG under Contracts Nos. Collaborative Research Center CRC 1044, FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) under Contract No. 530-4CDP03; Ministry of Development of Turkey under Contract No. DPT2006K-120470; National Science and Technology fund; STFC (United Kingdom); the Knut and Alice Wallenberg Foundation (Sweden) under Contract No. 2016.0157; the Royal Society, United Kingdom under Contracts No. DH140054 and No. DH160214; the Swedish Research Council; U.S. Department of Energy under Contracts No. DE-FG02-05ER41374, No. DE-SC-0010118, and No. DE-SC-0012069; University of Groningen (RuG), and the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), Darmstadt. This paper is also supported by Beijing municipal government under Contract No. CIT&TCD201704047 and by the Royal Society under Contract No. NF170002.