Measurement of the photon polarization in Λb0 → Λγ decays

LHCb collaboration

doi:10.1103/PhysRevD.105.L051104

Measurement of the photon polarization in Λb0 → Λγ decays

LHCb collaboration

Research output: Contribution to journal › Article › Academic › peer-review

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.

Original language	English
Article number	L051104
Number of pages	11
Journal	Physical Review D
Volume	105
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevD.105.L051104
Publication status	Published - 23 Mar 2022

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@article{29157349b4594c7ea3d53692e946fa88,

title = "Measurement of the photon polarization in Λb0 → Λγ decays",

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.",

author = "R. Aaij and A.S.W. Abdelmotteleb and C.A. Beteta and F. Abudinen and T. Ackernley and B. Adeva and M. Adinolfi and H. Afsharnia and C. Agapopoulou and C.A. Aidala and S. Aiola and Z. Ajaltouni and S. Akar and J. Albrecht and F. Alessio and M. Alexander and A.A. Albero and Z. Aliouche and G. Alkhazov and P.A. Cartelle and S. Amato and J.L. Amey 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 J.J. Back and P.B. Rodriguez and V. Balagura and W. Baldini and J.B. Leite and M. Barbetti and R.J. Barlow and S. Barsuk and W. Barter and M. Bartolini and \{LHCb collaboration\} and \{de Vries\}, J.A. and M. Merk and C.J. Pawley and K. Vos",

year = "2022",

month = mar,

day = "23",

doi = "10.1103/PhysRevD.105.L051104",

language = "English",

volume = "105",

journal = "Physical Review D",

issn = "1550-7998",

publisher = "American Physical Society",

number = "5",

}

TY - JOUR

T1 - Measurement of the photon polarization in Λb0 → Λγ decays

AU - Aaij, R.

AU - Abdelmotteleb, A.S.W.

AU - Beteta, C.A.

AU - Abudinen, F.

AU - Ackernley, T.

AU - Adeva, B.

AU - Adinolfi, M.

AU - Afsharnia, H.

AU - Agapopoulou, C.

AU - Aidala, C.A.

AU - Aiola, S.

AU - Ajaltouni, Z.

AU - Akar, S.

AU - Albrecht, J.

AU - Alessio, F.

AU - Alexander, M.

AU - Albero, A.A.

AU - Aliouche, Z.

AU - Alkhazov, G.

AU - Cartelle, P.A.

AU - Amato, S.

AU - Amey, J.L.

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 - Rodriguez, P.B.

AU - Balagura, V.

AU - Baldini, W.

AU - Leite, J.B.

AU - Barbetti, M.

AU - Barlow, R.J.

AU - Barsuk, S.

AU - Barter, W.

AU - Bartolini, M.

AU - LHCb collaboration

AU - de Vries, J.A.

AU - Merk, M.

AU - Pawley, C.J.

AU - Vos, K.

PY - 2022/3/23

Y1 - 2022/3/23

N2 - 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.

AB - 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.

U2 - 10.1103/PhysRevD.105.L051104

DO - 10.1103/PhysRevD.105.L051104

M3 - Article

SN - 1550-7998

VL - 105

JO - Physical Review D

JF - Physical Review D

IS - 5

M1 - L051104

ER -

Measurement of the photon polarization in Λb0 → Λγ decays

Abstract

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