We report the first evidence for isospin violation in B→K∗γ and the first measurement of the difference of CP asymmetries between B+→K∗+γ and B0→K∗0γ. This analysis is based on the data sample containing 772×106BB pairs that was collected with the Belle detector at the KEKB energy-asymmetric e+e- collider. We find evidence for the isospin violation with a significance of 3.1σ, Δ0+=[+6.2±1.5(stat)±0.6(syst)±1.2(f+-/f00)]%, where the third uncertainty is due to the uncertainty on the fraction of B+B- to B0B0 production in (4S) decays. The measured value is consistent with predictions of the standard model. The result for the difference of CP asymmetries is ΔACP=[+2.4±2.8(stat)±0.5(syst)]%, consistent with zero. The measured branching fractions and CP asymmetries for charged and neutral B meson decays are the most precise to date. We also calculate the ratio of branching fractions of B0→K∗0γ to Bs0→φγ.
Bibliographical noteFunding Information:
The authors would like to thank Roman Zwicky and David M. Straub for invaluable discussions. A. I. is supported by Japan Society for the Promotion of Science Grant No. 16H03968 and the Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence “Origin and Structure of the Universe.” We thank the KEKB group for the excellent operation of the accelerator, the KEK cryogenics group for the efficient operation of the solenoid, and the KEK computer group, the National Institute of Informatics, and the PNNL/EMSL computing group for valuable computing and SINET5 network support. We acknowledge support from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan, JSPS, and the Tau-Lepton Physics Research Center of Nagoya University, the Australian Research Council, the Austrian Science Fund under Grant No. P 26794-N20, the National Natural Science Foundation of China under Contracts No. 10575109, No. 10775142, No. 10875115, No. 11175187, No. 11475187, No. 11521505, and No. 11575017, the Chinese Academy of Science Center for Excellence in Particle Physics, the Ministry of Education, Youth and Sports of the Czech Republic under Contract No. LTT17020, the Carl Zeiss Foundation, the Deutsche Forschungsgemeinschaft, the Excellence Cluster Universe, and the VolkswagenStiftung, the Department of Science and Technology of India, the Istituto Nazionale di Fisica Nucleare of Italy, the WCU program of the Ministry of Education, National Research Foundation (NRF) of Korea under Grants No. 2011-0029457, No. 2012-0008143, No. 2014R1A2A2A01005286, No. 2014R1A2A2A01002734, No. 2015R1A2A2A01003280, No. 2015H1A2A1033649, No. 2016R1D1A1B01010135, No. 2016K1A3A7A09005603, No. 2016K1A3A7A09005604, No. 2016R1D1A1B02012900, No. 2016K1A3A7A09005606, No. NRF-2013K1A3A7A06056592, the Brain Korea 21-Plus program, Radiation Science Research Institute, Foreign Large-size Research Facility Application Supporting Project, and the Global Science Experimental Data Hub Center of the Korea Institute of Science and Technology Information, the Polish Ministry of Science and Higher Education and the National Science Center, the Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research, the Slovenian Research Agency; Ikerbasque, the Basque Foundation for Science and MINECO (Juan de la Cierva), Spain, the Swiss National Science Foundation, the Ministry of Education and the Ministry of Science and Technology of Taiwan, and the U.S. Department of Energy and the National Science Foundation.
© 2017 American Physical Society.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)