0864-084X 0864-084X S0864-084X2018000200037 USA 00 12 2018 00 12 2018 64 37 41

[1] 2014 38 090001 [2] THE LHCb COLLABORATION 2014 113 151601 [3] [4] 2017 95 115008 [5] 2007 99 231801 [6] 2005 74 11701(R) [7] 2008 11 011701 [8] 2010 05 026 [9] 2013 02 48 [10] 2003 576 62 [11] 2010 105 242001 [12] 2010 466 213 [13] 2012 84 1527 [14] 2013 339 417 [15] 2009 79 015014 [16] The KLOE collaboration 2009 64 627 [17] The NA62 collaboration 2013 719 326 [18] The TREK collaboration [19] The E36 collaboration [20] 1999 83 4253 [21] 2003 506 60 [22] 2000 440 151 [23] 2016 [24] 2015 8 024001