Constraints on the photon polarisation in b → sγ transitions using B s 0 → ϕe+e− decays
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13130_2025_Article_25703.pdf
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1.24 MB
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6d288aef0697709296c77ee8b476c9d0
Author(s)
Aaij, R.
Abdelmotteleb, A. S. W.
Abellan Beteta, C.
Abudinén, F.
Ackernley, T.
Adefisoye, A. A.
Adeva, B.
Adinolfi, M.
Adlarson, P.
Agapopoulou, C.
Date Issued
March 7, 2025
Journal
Journal of High Energy Physics
Publisher
Springer Berlin Heidelberg
Citation
The LHCb collaboration., Aaij, R., Abdelmotteleb, A.S.W. et al. Constraints on the photon polarisation in b → sγ transitions using B0 s → ϕe+e − decays.
Version
Final published version
Abstract
An angular analysis of the B s 0 → ϕe+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 ϕ meson is measured to be less than 11.5% at 90% confidence level. The A T R eCP observable, which is related to the lepton forward-backward asymmetry, is measured to be 0.116 ± 0.155 ± 0.006, where the first uncertainty is statistical and the second systematic. The transverse asymmetries, A T 2 and A T I mCP , which are sensitive to the virtual photon polarisation, are found to be −0.045 ± 0.235 ± 0.014 and 0.002 ± 0.247 ± 0.016, respectively. The results are consistent with Standard Model predictions.
MIT Department
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1007/JHEP03(2025)047
