K +→π + π 0 e + e −: a novel short-distance probe L. Cappiello, O. Catà, G. D’Ambrosio and Dao-Neng Gao Eur. Phys. J. C, 72 1 (2012) 1872 Published online: 31 January 2012 DOI: 10.1140/epjc/s10052-012-1872-x