Angular analysis of the B0 → K*0e+e− decay in the low-q2 region

Abstract

Abstract: An angular analysis of the B0 → K*0e+e− decay is performed using a data sample, corresponding to an integrated luminosity of 3.0 fb−1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV during 2011 and 2012. For the first time several observables are measured in the dielectron mass squared (q2) interval between 0.002 and 1.120 GeV2/c4. The angular observables FL and ATRe which are related to the K*0 polarisation and to the lepton forward-backward asymmetry, are measured to be FL = 0.16 ± 0.06 ± 0.03 and ATRe = 0.10 ± 0.18 ± 0.05, where the first uncertainty is statistical and the second systematic. The angular observables AT(2) and ATIm which are sensitive to the photon polarisation in this q2 range, are found to be AT(2) = − 0.23 ± 0.23 ± 0.05 and ATIm = 0.14 ± 0.22 ± 0.05. The results are consistent with Standard Model predictions.[Figure not available: see fulltext.]