Study of the K+ -> e+ nu e+ e- Decay with the NA62 Experiment

I joined a study concerning measurements of the branching ratio and the form factors of the rare decay K+ → e+ ν e+ e− (Ke2ee) with the NA62 experiment. With the data collected between 2016 and 2021, NA62 has currently a Ke2ee sample, large enough to significantly improve the state of the art. Preliminary studies show that it is possible to reach an almost background-free selection of Ke2ee decays, while maintaining a sizeable amount of signal events. In 2022, new data is being collected with the opportunity to achieve the largest Ke2ee sample in the world, suitable for improving the statistical uncertainty of the branching ratio and the form factors measurements. I took part in the analysis of the 2017-2018 data sample: with the NA62 framework, producing histograms both with data and Monte Carlo simulations, building a signal selection, statistically interpreting the data and evaluating uncertainties.