Abstrakt
A sample of 1.3 x 10(5)K+? p(0)e(+)?? candidates with less than 1% background was collected by the NA62 experiment at the CERN SPS in 2017-2018. Branching fraction measurements are obtained at percent relative precision in three restricted kinematic regions, improving on existing results by a factor larger than two.
An asymmetry, possibly related to T-violation, is investigated with no evidence observed within the achieved precision.