Using an e+e- A nnihilation data sample corresponding to an integrated luminosity of 2.93 fb-1 collected at the center-of-mass energy of 3.773 GeV with the BESIII detector, we measure the absolute branching fractions of D+→ηηπ+, D+→ηπ+π0, and D0→ηπ+π-to be (2.96±0.24±0.10)×10-3, (2.23±0.15±0.10)×10-3, and (1.20±0.07±0.04)×10-3, respectively, where the first uncertainties are statistical and the second ones are systematic. The D+→ηηπ+ decay is observed for the first time, and the branching fractions of D+(0)→ηπ+π0(-) are measured with much improved precision. In addition we test for CP asymmetries in the separated charge-conjugate branching fractions; no evidence of CP violation is found.
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. 11775230, No. 11475123, No. 11625523, No. 11635010, No. 11735014, No. 11822506, No. 11835012, No. 11935015, No. 11935016, No. 11935018, and No. 11961141012; 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. U1532101, No. U1732263, No. U1832207, and No. U1932102; 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 Collaborative Research Center Contracts No. CRC 1044 and No. FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy; 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, U.K., under Contracts No. DH140054 and No. DH160214; The Swedish Research Council; and U.S. Department of Energy under Contracts No. DE-FG02-05ER41374 and No. DE-SC-0012069.