Measurement of the T-Odd Correlation in the K+ → π0e+νeγ Radiative Decay at the OKA Setup

Abstract

The T-odd correlation $${{\xi }_{{\pi e\gamma }}}$$ , which is the mixed product of the momenta of $${{e}^{ + }}$$ , $${{\pi }^{0}}$$ , and γ in the system of rest of the kaon divided by $$M_{K}^{3}$$ , has been measured in the K+ → π0e+νeγ radiative decay among 101 200 candidate events detected at the OKA setup. The asymmetry of the distribution in $${{\xi }_{{\pi e\gamma }}}$$ is characterized by the ratio $${{A}_{\xi }} = \frac{{{{N}_{ + }} - {{N}_{ - }}}}{{{{N}_{ + }} + {{N}_{ - }}}}$$ , where $${{N}_{{ + ( - )}}}$$ is the number of events with positive (negative) ξ. The value $${{A}_{\xi }}$$ = (+0.1 ± 3.9(stat.) ± 1.7(syst.)) × 10–3 or $${\text{|}}{{A}_{\xi }}{\text{|}} < 5.4 \times {{10}^{{ - 3}}}$$ (90% C.L.) has been obtained.