Measurement of CP asymmetry in D0 → K0SK0S decays with Run 3 data

LHCb Collaboration; Lorenzo Pica; Marco Adinolfi; Jake Amey; Jozie Cottee Meldrum; Zahra Ghorbanimoghaddam; Alex M Marshall; Camille A Normand; Konstantinos A.  Petridis; Jonas H Rademacker; Jake Reich; Anatoly Solomin; Jaap J Velthuis; Rui Wang; Benedict D C Westhenry; Sean J Williams; Zak Williams

doi:10.1007/JHEP02(2026)253

Measurement of CP asymmetry in D⁰→ K⁰_SK⁰_S decays with Run 3 data

LHCb Collaboration, Lorenzo Pica^*, Marco Adinolfi, Jake Amey, Jozie Cottee Meldrum, Zahra Ghorbanimoghaddam, Alex M Marshall, Camille A Normand, Konstantinos A. Petridis, Jonas H Rademacker, Jake Reich, Anatoly Solomin, Jaap J Velthuis, Rui Wang, Benedict D C Westhenry, Sean J Williams, Zak Williams

^*Corresponding author for this work

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

Abstract

A measurement of CP asymmetry in D⁰→ K⁰_SK⁰_S decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 6.2 fb⁻¹. The D⁰→ K⁰_Sπ⁺π⁻ decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated CP asymmetry for the D⁰→ K⁰_SK⁰_S mode is measured to be
A^CP (D⁰→ K⁰_SK⁰_S) = (1.86 ± 1.04 ± 0.41)%,
where the first uncertainty is statistical, and the second is systematic. This measurement represents the most precise single-experiment determination of this quantity to date.

Original language	English
Article number	253
Number of pages	25
Journal	Journal of High Energy Physics
Volume	2026
Issue number	2
DOIs	https://doi.org/10.1007/JHEP02(2026)253
Publication status	Published - 26 Feb 2026

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Copyright © 2026, The Author(s)

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© The Author(s) 2026.

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LHCb Collaboration, Pica, L., Adinolfi, M., Amey, J., Cottee Meldrum, J., Ghorbanimoghaddam, Z., Marshall, A. M., Normand, C. A., Petridis, K. A., Rademacker, J. H., Reich, J., Solomin, A., Velthuis, J. J., Wang, R., Westhenry, B. D. C., Williams, S. J., & Williams, Z. (2026). Measurement of CP asymmetry in D⁰→ K⁰_SK⁰_S decays with Run 3 data. Journal of High Energy Physics, 2026(2), Article 253. https://doi.org/10.1007/JHEP02(2026)253

@article{d146ec7244d942459b25c209263e3b27,

title = "Measurement of CP asymmetry in D0 → K0SK0S decays with Run 3 data",

abstract = "A measurement of CP asymmetry in D0 → K0SK0S decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 6.2 fb−1. The D0 → K0Sπ+π− decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated CP asymmetry for the D0 → K0SK0S mode is measured to be ACP (D0 → K0SK0S) = (1.86 ± 1.04 ± 0.41)\%, where the first uncertainty is statistical, and the second is systematic. This measurement represents the most precise single-experiment determination of this quantity to date. ",

author = "\{LHCb Collaboration\} and Lorenzo Pica and Marco Adinolfi and Jake Amey and \{Cottee Meldrum\}, Jozie and Zahra Ghorbanimoghaddam and Marshall, \{Alex M\} and Normand, \{Camille A\} and Petridis, \{Konstantinos A.\} and Rademacker, \{Jonas H\} and Jake Reich and Anatoly Solomin and Velthuis, \{Jaap J\} and Rui Wang and Westhenry, \{Benedict D C\} and Williams, \{Sean J\} and Zak Williams",

note = "Copyright {\textcopyright} 2026, The Author(s) Publisher Copyright: {\textcopyright} The Author(s) 2026.",

year = "2026",

month = feb,

day = "26",

doi = "10.1007/JHEP02(2026)253",

language = "English",

volume = "2026",

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LHCb Collaboration, Pica, L, Adinolfi, M, Amey, J, Cottee Meldrum, J, Ghorbanimoghaddam, Z, Marshall, AM, Normand, CA, Petridis, KA , Rademacker, JH , Reich, J , Solomin, A , Velthuis, JJ, Wang, R, Westhenry, BDC, Williams, SJ & Williams, Z 2026, 'Measurement of CP asymmetry in D⁰→ K⁰_SK⁰_S decays with Run 3 data', Journal of High Energy Physics, vol. 2026, no. 2, 253. https://doi.org/10.1007/JHEP02(2026)253

TY - JOUR

T1 - Measurement of CP asymmetry in D0 → K0SK0S decays with Run 3 data

AU - LHCb Collaboration

AU - Pica, Lorenzo

AU - Adinolfi, Marco

AU - Amey, Jake

AU - Cottee Meldrum, Jozie

AU - Ghorbanimoghaddam, Zahra

AU - Marshall, Alex M

AU - Normand, Camille A

AU - Petridis, Konstantinos A.

AU - Rademacker, Jonas H

AU - Reich, Jake

AU - Solomin, Anatoly

AU - Velthuis, Jaap J

AU - Wang, Rui

AU - Westhenry, Benedict D C

AU - Williams, Sean J

AU - Williams, Zak

PY - 2026/2/26

Y1 - 2026/2/26

N2 - A measurement of CP asymmetry in D0 → K0SK0S decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 6.2 fb−1. The D0 → K0Sπ+π− decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated CP asymmetry for the D0 → K0SK0S mode is measured to be ACP (D0 → K0SK0S) = (1.86 ± 1.04 ± 0.41)%, where the first uncertainty is statistical, and the second is systematic. This measurement represents the most precise single-experiment determination of this quantity to date.

AB - A measurement of CP asymmetry in D0 → K0SK0S decays is reported, based on a data sample of proton-proton collisions collected with the LHCb detector in 2024 at a centre-of-mass energy of 13.6 TeV, corresponding to an integrated luminosity of 6.2 fb−1. The D0 → K0Sπ+π− decay is used as calibration channel to cancel residual detection and production asymmetries. The time-integrated CP asymmetry for the D0 → K0SK0S mode is measured to be ACP (D0 → K0SK0S) = (1.86 ± 1.04 ± 0.41)%, where the first uncertainty is statistical, and the second is systematic. This measurement represents the most precise single-experiment determination of this quantity to date.

U2 - 10.1007/JHEP02(2026)253

DO - 10.1007/JHEP02(2026)253

M3 - Article (Academic Journal)

SN - 1029-8479

VL - 2026

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 2

M1 - 253

ER -