Searches for the light invisible hypothetic pseudoscalar in K + → π + π 0 P decay

Abstract

Abstract A high statistics data sample of the K + decays was recorded in 2012 and 2013 by the OKA collaboration. The missing mass analysis was performed to search for the light invisible pseudoscalar P in the decay K + → π + π 0 P for two alternative scenarios, namely for the pseudoscalar sgoldstino and for the axion. No signal is observed, the upper limits for the branching ratio of the decay are derived for both scenarios. The 90% CL upper limit for the case of sgoldstino is estimated to be in the region from 2 · 10−5 to 1 · 10−6 for the sgoldsino mass from 20 to 200 MeV and for the case of axion the upper limit is changing from 1 · 10−5 to 1 · 10−6 for the same mass range.