An Angular Analysis of $B^+ \to K^+e^+e^-$ Decays at the LHCb Experiment

Recent anomalies in the $b\to s\ell\ell$ sector point towards possible Lepton Flavour Universality (LFU) violating effects coupling to (axial-)vector currents. An angular analysis of the differential decay rate of $B^+ \to K^+ e^+e^-$ decays is used to measure the observables $A_{FB}$ and $F_H$ using data from $pp$ collisions gathered at the LHCb experiment between 2011 and 2016. This dataset corresponds to a total integrated luminosity of $5\textrm{fb}^{-1}$. The angular observables $A_{FB}$ and $F_H$ are only sensitive to (pseudo-)scalar and (pseudo-)tensor couplings for Standard Model (SM) like values of the observables, which therefore provides an avenue to check LFU effects and to validate the electron reconstruction at the LHCb experiment. The decay distribution is fit using a binned likelihood method, and angular observables are presented as a likelihood surface using a two dimensional Feldman Cousins construct. The result of the likelihood fit is compatible with the Standard Model prediction within $1\sigma$. This angular analysis is the first of its kind.