2017/01/24 by N. Lurkin, Lurkin, Nicolas
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Neutrino Physics Research #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.1701.06979
openalex publication_date 2017/01/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The NA48/2 and NA62-RK experiments at the CERN SPS collected a large sample of charged kaon decays in flight. NA62-RK was running in 2007-08 with a highly efficient minimum bias trigger for decays into electrons. A preliminary measurement of the electromagnetic transition form factor slope of the π0 from 1.05× 106 fully reconstructed π0 Dalitz decays is presented. The obtained value a = (3.70 ± 0.53stat ± 0.36syst)× 10-2 represents a 5.8σ observation of a non-zero slope in the time-like region of momentum transfer. An upper limit on the rate of a lepton number violating decay K^±→π^∓μ^±μ^± is reported from ∼ 1.6× 1011 K^± decays at NA48/2 in 2003-04: B < 8.6× 10-11 at 90 % CL. Searches for heavy sterile neutrino N4 and inflaton χ resonances in K^±→πμμ decays are reported. No signal is observed and upper limits on the products B(K^±→μ^± N4)B(N4→π^∓μ^±) and B(K^±→π^± χ)B(χ→μ+μ-) are set in the range 10-10-10-9 for resonance lifetimes up to 100~ps. The result of a search for dark photon with the same sample of decays is also reported. In the absence of observed signal, the limits on the mixing parameter ε2 in the range 9-70~MeV/c2 are improved.