Strong constraints on the b → sγ photon polarisation from B0 → K*0e+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...
| Main Authors: | , , , , , , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
Springer Berlin Heidelberg
2021
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| Online Access: | https://hdl.handle.net/1721.1/131824 |
| _version_ | 1826204297000386560 |
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| author | 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. |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics 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. |
| author_sort | Aaij, R. |
| collection | MIT |
| description | 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
A
T
Re
$$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$
observable, which is related to the lepton forward-backward asymmetry, is measured to be
A
T
Re
$$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$
= −0.06 ± 0.08 ± 0.02. The
A
T
2
$$ {A}_{\mathrm{T}}^{(2)} $$
and
A
T
Im
$$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$
transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be
A
T
2
$$ {A}_{\mathrm{T}}^{(2)} $$
= 0.11 ± 0.10 ± 0.02 and
A
T
Im
$$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$
= 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. |
| first_indexed | 2024-09-23T12:52:03Z |
| format | Article |
| id | mit-1721.1/131824 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T12:52:03Z |
| publishDate | 2021 |
| publisher | Springer Berlin Heidelberg |
| record_format | dspace |
| spelling | mit-1721.1/1318242023-12-12T15:42:56Z Strong constraints on the b → sγ photon polarisation from B0 → K*0e+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. Massachusetts Institute of Technology. Department of Physics 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 A T Re $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ observable, which is related to the lepton forward-backward asymmetry, is measured to be A T Re $$ {A}_{\mathrm{T}}^{\mathrm{Re}} $$ = −0.06 ± 0.08 ± 0.02. The A T 2 $$ {A}_{\mathrm{T}}^{(2)} $$ and A T Im $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ transverse asymmetries, which are sensitive to the virtual photon polarisation, are found to be A T 2 $$ {A}_{\mathrm{T}}^{(2)} $$ = 0.11 ± 0.10 ± 0.02 and A T Im $$ {A}_{\mathrm{T}}^{\mathrm{Im}} $$ = 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. 2021-09-20T17:30:26Z 2021-09-20T17:30:26Z 2020-12-11 2020-12-20T04:51:54Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/131824 Journal of High Energy Physics. 2020 Dec 11;2020(12):81 PUBLISHER_CC en https://doi.org/10.1007/JHEP12(2020)081 Creative Commons Attribution https://creativecommons.org/licenses/by/4.0/ The Author(s) application/pdf Springer Berlin Heidelberg Springer Berlin Heidelberg |
| spellingShingle | 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. Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title | Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title_full | Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title_fullStr | Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title_full_unstemmed | Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title_short | Strong constraints on the b → sγ photon polarisation from B0 → K*0e+e− decays |
| title_sort | strong constraints on the b sγ photon polarisation from b0 k 0e e decays |
| url | https://hdl.handle.net/1721.1/131824 |
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