The decay-time-dependent CP asymmetry in Bs0->J/Psi(->mu+mu-)K+K- decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb-1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0 signal decays with an invariant K+K- mass in the vicinity of the Phi(1020) resonance, the CP-violating phase φs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0-Bs0bar system, DeltaGammas, and the difference of the average Bs0 and B0 meson decay widths, Gs-Gd. The values obtained are Phis=-0.039 \pm 0.022 \pm 0.006 rad, DGs=0.0845\pm0.0044 \pm 0.0024 ps-1, and Gs-Gd=-0.056-0.0015+0.0013 \pm0.0014 ps-1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase φs is also measured independently for each polarization state of the K+K- system and shows no evidence for polarization dependence.

Improved Measurement of CP Violation Parameters in Bs0 ->J/PsiK+K- Decays in the Vicinity of the Phi(1020) Resonance

Bassi G.
Membro del Collaboration Group
;
Kleijne N.
Membro del Collaboration Group
;
Morello M. J.
Membro del Collaboration Group
;
Pica L.
Membro del Collaboration Group
;
Ribatti R.
Membro del Collaboration Group
;
2024

Abstract

The decay-time-dependent CP asymmetry in Bs0->J/Psi(->mu+mu-)K+K- decays is measured using proton-proton collision data, corresponding to an integrated luminosity of 6 fb-1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. Using a sample of approximately 349 000 Bs0 signal decays with an invariant K+K- mass in the vicinity of the Phi(1020) resonance, the CP-violating phase φs is measured, along with the difference in decay widths of the light and heavy mass eigenstates of the Bs0-Bs0bar system, DeltaGammas, and the difference of the average Bs0 and B0 meson decay widths, Gs-Gd. The values obtained are Phis=-0.039 \pm 0.022 \pm 0.006 rad, DGs=0.0845\pm0.0044 \pm 0.0024 ps-1, and Gs-Gd=-0.056-0.0015+0.0013 \pm0.0014 ps-1, where the first uncertainty is statistical and the second systematic. These are the most precise single measurements to date and are consistent with expectations based on the Standard Model and with the previous LHCb analyses of this decay. These results are combined with previous independent LHCb measurements. The phase φs is also measured independently for each polarization state of the K+K- system and shows no evidence for polarization dependence.
Improved Measurement of CP Violation Parameters in Bs0 →j/ψK+K- Decays in the Vicinity of the φ (1020) Resonance
2024
Settore FIS/01 - Fisica Sperimentale
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
Width difference; phase phi(s); b-s(0); j/psi; 1st
   The flavour of New Physics in the loops of hadronic beauty decays
   UK Research and Innovation
   Horizon Europe Guarantee
   EP/X014746/2

   Getting a flavour for New Physics with precision measurements of tree-level beauty decays
   UK Research and Innovation
   STFC
   ST/R004536/2

   Getting a flavour for New Physics with precision measurements of tree-level beauty decays
   UK Research and Innovation
   STFC
   ST/R004536/3
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/153967
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