Search for light pseudoscalar sgoldstino in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:msup><mml:mi>K</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:math> decays

A search for the light pseudoscalar sgoldstino production in the three-body K− decay K−→π−π0P has been performed with the “ISTRA+” detector exposed to the 25 GeV/c negative secondary beam of the U-70 proton synchrotron. No signal is observed. An upper limit for the branching ratio Br(K−→π−π0P), at 90% confidence level, is determined to be ∼9×10−6 in the effective mass mP range from 0 to 200 MeV/c2, excluding the region near mπ0 where it degrades to ∼3.5×10−5.