Stefan Weinzierl¹, Konglong Wu⁵, and Xiaofeng Xu^1,6 ($ϵ$ Collaboration)

• ¹PRISMA Cluster of Excellence, Institut für Physik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany
• ²Bethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn, Germany
• ³Paul Scherrer Institut, CH-5232 Villigen, Switzerland
• ⁴School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China
• ⁵School of Physics and Technology, Wuhan University, Wuhan 430072, China
• ⁶Department of Physics, Xiamen University, Xiamen 361005, China