Constraints on the photon polarisation in b->s gamma transitions using Bs0-> Phie+e- decays

An angular analysis of the Bs0-> phi e+e- decay is performed using the proton-proton collision dataset collected between 2011 and 2018 by the LHCb experiment, corresponding to an integrated luminosity of 9 fb-1 at centre-of-mass energies of 7, 8 and 13 TeV. The analysis is performed in the very low dielectron invariant mass-squared region between 0.0009 and 0.2615 GeV2/c4. The longitudinal polarisation fraction of the phi meson is measured to be less than 11.5% at 90% confidence level. The ATReCP observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116 \pm 0.155 \pm 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, AT2 and ATImCP, which are sensitive to the virtual photon polarisation, are found to be -0.045 \pm 0.235 \pm 0.014 and 0.002 \pm 0.247 \pm 0.016, respectively. The results are consistent with Standard Model predictions.