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 3fb −1 , nearly 14000 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→sγ transition is reported with a significance of 5.2σ .

Observation of Photon Polarization in the b→sγ Transition

AURIEMMA, Giulio;SATRIANO, Celestina;
2014-01-01

Abstract

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 3fb −1 , nearly 14000 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→sγ transition is reported with a significance of 5.2σ .
2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11563/78500
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