The photon polarization in b→sγ transitions is measured for the first time in radiative b-baryon decays exploiting the unique spin structure of Λb0→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=0.82-0.26-0.13+0.17+0.04, 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.

Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adeva, B., et al. (2022). Measurement of the photon polarization in Λb0 → Λγ decays. PHYSICAL REVIEW D, 105(5) [10.1103/PhysRevD.105.L051104].

Measurement of the photon polarization in Λb0 → Λγ decays

Borsato M.;Calvi M.;Capelli S.;Carniti P.;Fazzini D.;Garcia Pardinas J.;Gotti C.;Martinazzoli L.;Martinelli M.;Meloni S.;Minotti A.;Petruzzo M.;Pizzichemi M.;Salomoni M.;Shields E. B.;
2022

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 Λb0→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=0.82-0.26-0.13+0.17+0.04, 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.
Articolo in rivista - Articolo scientifico
Leptons; Mesons; Deterioration;
English
23-mar-2022
2022
105
5
L051104
none
Aaij, R., Abdelmotteleb, A., Abellan Beteta, C., Abudinen, F., Ackernley, T., Adeva, B., et al. (2022). Measurement of the photon polarization in Λb0 → Λγ decays. PHYSICAL REVIEW D, 105(5) [10.1103/PhysRevD.105.L051104].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/372890
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