The photon polarization in b→sγ transitions is measured for the first time in radiative b -baryon decays exploiting the unique spin structure of Λ0b→Λγ decays. A data sample corresponding to an integrated luminosity of 6  fb−1 collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV is used. The photon polarization is measured to be αγ=0.82+0.17+0.04−0.26−0.13, where the first uncertainty is statistical and the second systematic. This result is in agreement with the Standard Model prediction and previous measurements in b -meson decays. Charge-parity breaking effects are studied for the first time in this observable and found to be consistent with CP symmetry.

Measurement of the photon polarization in Λ0b → Λ γ decays

D. Brundu;F. Dettori;G. Manca;R. Oldeman;B. Saitta;
2022-01-01

Abstract

The photon polarization in b→sγ transitions is measured for the first time in radiative b -baryon decays exploiting the unique spin structure of Λ0b→Λγ decays. A data sample corresponding to an integrated luminosity of 6  fb−1 collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV is used. The photon polarization is measured to be αγ=0.82+0.17+0.04−0.26−0.13, where the first uncertainty is statistical and the second systematic. This result is in agreement with the Standard Model prediction and previous measurements in b -meson decays. Charge-parity breaking effects are studied for the first time in this observable and found to be consistent with CP symmetry.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/343734
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