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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/133074
Observation of Photon Polarization in the b→sγ Transition
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This Letter presents a study of the flavor-changing neutral current radiative B ± → K ± π ∓ π ± γ decays performed using data collected in proton-proton collisions with the LHCb detector at 7 and 8 TeV center-of-mass energies. In this sample, corresponding to an integrated luminosity of 3 fb − 1 , nearly 14 000 signal events are reconstructed and selected, containing all possible intermediate resonances with a K ± π ∓ π ± final state in the [ 1.1 , 1.9 ] GeV / c 2 mass range. The distribution of the angle of the photon direction with respect to the plane defined by the final-state hadrons in their rest frame is studied in intervals of K ± π ∓ π ± mass and the asymmetry between the number of signal events found on each side of the plane is obtained. The first direct observation of the photon polarization in the b → s γ transition is reported with a significance of 5.2 σ .
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BADALOV, Alexey, et al. Observation of Photon Polarization in the b→sγ Transition. Physical Review Letters. 2014. Vol. 112, num. 16, pags. 161801. ISSN 0031-9007. [consulted: 10 of October of 2026]. Available at: https://hdl.handle.net/2445/133074