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Updated: Sep 20, 2025

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Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
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Observation of B (2S)K and B (2S)K decays
A Tumasyan1, W Adam2, J W Andrejkovic2
1Yerevan Physics Institute, Yerevan, Armenia.
Summary
The CMS experiment observed B0 and Bs0 meson decays using proton-proton collisions. New measurements provide the first branching fraction ratios for these decays, crucial for understanding particle physics.
Area of Science:
- High Energy Physics
- Particle Physics
- Quantum Chromodynamics
Background:
- The Standard Model of particle physics describes fundamental particles and forces.
- Understanding meson decays provides insights into fundamental interactions.
- Previous measurements lacked precision in branching fraction ratios.
Purpose of the Study:
- To observe and measure the branching fraction ratios of B0 and Bs0 meson decays.
- To provide precise measurements for the first time.
- To test predictions of the Standard Model and Quantum Chromodynamics.
Main Methods:
- Analysis of proton-proton collision data collected by the CMS experiment at the LHC.
- Utilizing data from 2017 and 2018 with a specific integrated luminosity.
- Statistical analysis to achieve significances exceeding 5 standard deviations for the observed decays.
Main Results:
- Observation of B0 and Bs0 meson decays with high statistical significance.
- First-time measurement of branching fraction ratios: B(B0 -> J/psi phi) / B(Bs0 -> J/psi phi) = 0.0448 +/- 0.0006 (stat) +0.0005/-0.0004 (syst) +/- 0.0004 (lumi) +/- 0.0005 (prod).
- Measurement of B(B0 -> J/psi K*) / B(Bs0 -> J/psi phi) = 0.055 +/- 0.001 (stat) +0.001/-0.001 (syst) +/- 0.001 (lumi) +/- 0.001 (prod).
Conclusions:
- The observed decays and measured ratios provide crucial data for particle physics.
- These results offer new constraints for theoretical models in Quantum Chromodynamics.
- Further analysis can refine understanding of heavy quarkonium decays.
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