An angular analysis of the B0 → K*0e+e− decay is performed using a data sample corresponding to an integrated luminosity of 9 fb−1 of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q2) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B0 → K*0γ transition with a virtual photon. The fraction of longitudinal polarisation of the K*0 meson, FL, is measured to be FL = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The ReT observable, which is related to the lepton forward-backward asymmetry, is measured to be ReT = −0.06 ± 0.08 ± 0.02. The (2)T and ImT transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be (2)T = 0.11 ± 0.10 ± 0.02 and ImT = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world’s best constraint on the b → sγ photon polarisation.

Strong constraints on the b → sγ photon polarisation from B 0 → K *0 e + e − decays / Aaij, R., Abellán Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., Aidala, C.A., Aiola, S., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Aliouche, Z., Alkhazov, G., Alvarez Cartelle, P., Amato, S., Amhis, Y., An, L., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2020:12(2020). [10.1007/JHEP12(2020)081]

Strong constraints on the b → sγ photon polarisation from B 0 → K *0 e + e − decays

Capriotti, L.;Casse, G.;Sarti, A.;Sciubba, A.;
2020

Abstract

An angular analysis of the B0 → K*0e+e− decay is performed using a data sample corresponding to an integrated luminosity of 9 fb−1 of pp collisions collected with the LHCb experiment. The analysis is conducted in the very low dielectron mass squared (q2) interval between 0.0008 and 0.257 GeV2, where the rate is dominated by the B0 → K*0γ transition with a virtual photon. The fraction of longitudinal polarisation of the K*0 meson, FL, is measured to be FL = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The ReT observable, which is related to the lepton forward-backward asymmetry, is measured to be ReT = −0.06 ± 0.08 ± 0.02. The (2)T and ImT transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be (2)T = 0.11 ± 0.10 ± 0.02 and ImT = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world’s best constraint on the b → sγ photon polarisation.
2020
rare decay; flavour changing neutral currents; polarization; B physics; Hadron-Hadron scattering (experiments)
01 Pubblicazione su rivista::01a Articolo in rivista
Strong constraints on the b → sγ photon polarisation from B 0 → K *0 e + e − decays / Aaij, R., Abellán Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., Aidala, C.A., Aiola, S., Ajaltouni, Z., Akar, S., Albrecht, J., Alessio, F., Alexander, M., Alfonso Albero, A., Aliouche, Z., Alkhazov, G., Alvarez Cartelle, P., Amato, S., Amhis, Y., An, L., et al.. - In: JOURNAL OF HIGH ENERGY PHYSICS. - ISSN 1029-8479. - 2020:12(2020). [10.1007/JHEP12(2020)081]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1579986
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