First search for K+→π+νν¯ using t

New Physics Implications of Recent Search for KL→π0νν¯Kitahara1, Okui2, Pérez3 et al. 2020Phys. Rev. Lett.7911260View full textAdd to dashboardCite

“…The upper bound on two body decay B(K + → π + X) is O(10 −10 − 10 −11 ) [9], which is generally stronger than that on B(K + → π + νν) except for near the neutral pion mass |m X − m π 0 | 25 MeV and above two pion mass threshold m X 2m π 0 , because the search is suffered from K + → π + π 0 (γ), π + + 2π backgrounds [7,9,32,33]. For example, for m X = (0) 100 MeV the expected number of events in KOTO is bound to be smaller than 0.7 (0.3) at 90 % CL.…”

Recent kaon decay results from NA62

“…One event was observed in R2, as shown in Fig. 2, corresponding to a p-value of 15% for the background only hypothesis and an observed upper limit of B(K + → π + νν) < 14 × 10 −10 at 95 % CL [9].…”

“…Reconstructed m 2 miss of the 2016 data as a function of the π + momentum for events satisfying the K + → π + νν selection[9]. The gray area corresponds to the distribution of MC signal events.…”

“…Summary of the background estimates summed over the two signal regions for the analysis of the 2016 data-set[9].…”

Opportunities for Lattice QCD in quark and lepton flavor physics

“…NA62 aims to measure the branching fraction of the rare kaon decay K + → π + νν with approximately 10% uncertainty [31], following up on Brookhaven E949 [32]. A first candidate event was observed in 2018 [33]. KOTO focuses on the similar rare kaon decay K L → π 0 νν [34], and first results were also published in 2018 [35].…”