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

The LHCb collaboration

doi:10.1007/JHEP12(2020)081

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

The LHCb collaboration

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Résultats de recherche: Contribution à un journal › Article › Revue par des pairs

Résumé

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, F_L, is measured to be F_L = (4.4 ± 2.6 ± 1.4)%, where the first uncertainty is statistical and the second systematic. The ATRe observable, which is related to the lepton forward-backward asymmetry, is measured to be ATRe = −0.06 ± 0.08 ± 0.02. The AT(2) and ATIm transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be AT(2) = 0.11 ± 0.10 ± 0.02 and ATIm = 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. [Figure not available: see fulltext.]

langue originale	Anglais
Numéro d'article	81
journal	Journal of High Energy Physics
Volume	2020
Numéro de publication	12
Les DOIs	https://doi.org/10.1007/JHEP12(2020)081
état	Publié - 1 déc. 2020

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10.1007/JHEP12(2020)081

Contient cette citation

@article{a0b609680c0c4844b6123b45916d7400,

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

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 ATRe observable, which is related to the lepton forward-backward asymmetry, is measured to be ATRe = −0.06 ± 0.08 ± 0.02. The AT(2) and ATIm transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be AT(2) = 0.11 ± 0.10 ± 0.02 and ATIm = 0.02 ± 0.10 ± 0.01. The results are consistent with Standard Model predictions and provide the world{\textquoteright}s best constraint on the b → sγ photon polarisation. [Figure not available: see fulltext.]",

keywords = "B physics, Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Polarization, Rare decay",

author = "\{The LHCb collaboration\} and R. Aaij and \{Abell{\'a}n Beteta\}, C. and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and Aidala, \{C. A.\} and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and \{Alfonso Albero\}, A. and Z. Aliouche and G. Alkhazov and \{Alvarez Cartelle\}, P. and S. Amato and Y. Amhis and L. An and L. Anderlini and A. Andreianov and M. Andreotti and F. Archilli and A. Artamonov and M. Artuso and K. Arzymatov and E. Aslanides and M. Atzeni and B. Audurier and S. Bachmann and M. Bachmayer and Back, \{J. J.\} and S. Baker and \{Baladron Rodriguez\}, P. and V. Balagura and W. Baldini and \{Baptista Leite\}, J. and Barlow, \{R. J.\} and S. Barsuk and W. Barter and M. Bartolini and F. Baryshnikov and Basels, \{J. M.\} and G. Bassi and B. Batsukh and A. Battig and A. Bay and F. Fleuret and E. Maurice",

note = "Publisher Copyright: {\textcopyright} 2020, The Author(s).",

year = "2020",

month = dec,

day = "1",

doi = "10.1007/JHEP12(2020)081",

language = "English",

volume = "2020",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

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T1 - Strong constraints on the b → sγ photon polarisation from B 0 → K *0 e + e − decays

AU - The LHCb collaboration

AU - Aaij, R.

AU - Abellán Beteta, C.

AU - Ackernley, T.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Afsharnia, H.

AU - Aidala, C. A.

AU - Aiola, S.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Alfonso Albero, A.

AU - Aliouche, Z.

AU - Alkhazov, G.

AU - Alvarez Cartelle, P.

AU - Amato, S.

AU - Amhis, Y.

AU - An, L.

AU - Anderlini, L.

AU - Andreianov, A.

AU - Andreotti, M.

AU - Archilli, F.

AU - Artamonov, A.

AU - Artuso, M.

AU - Arzymatov, K.

AU - Aslanides, E.

AU - Atzeni, M.

AU - Audurier, B.

AU - Bachmann, S.

AU - Bachmayer, M.

AU - Back, J. J.

AU - Baker, S.

AU - Baladron Rodriguez, P.

AU - Balagura, V.

AU - Baldini, W.

AU - Baptista Leite, J.

AU - Barlow, R. J.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - Baryshnikov, F.

AU - Basels, J. M.

AU - Bassi, G.

AU - Batsukh, B.

AU - Battig, A.

AU - Bay, A.

AU - Fleuret, F.

AU - Maurice, E.

PY - 2020/12/1

Y1 - 2020/12/1

N2 - 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 ATRe observable, which is related to the lepton forward-backward asymmetry, is measured to be ATRe = −0.06 ± 0.08 ± 0.02. The AT(2) and ATIm transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be AT(2) = 0.11 ± 0.10 ± 0.02 and ATIm = 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. [Figure not available: see fulltext.]

AB - 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 ATRe observable, which is related to the lepton forward-backward asymmetry, is measured to be ATRe = −0.06 ± 0.08 ± 0.02. The AT(2) and ATIm transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be AT(2) = 0.11 ± 0.10 ± 0.02 and ATIm = 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. [Figure not available: see fulltext.]

KW - B physics

KW - Flavour Changing Neutral Currents

KW - Hadron-Hadron scattering (experiments)

KW - Polarization

KW - Rare decay

U2 - 10.1007/JHEP12(2020)081

DO - 10.1007/JHEP12(2020)081

M3 - Article

AN - SCOPUS:85097537572

SN - 1126-6708

VL - 2020

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 12

M1 - 81

ER -

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

Résumé

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