This is a report of the LHCb experiment.
The LHCb experiment will use detectors upgraded for LHC Run 3 to prepare for data acquisition, thus continuing the rich collection of results using data collected in Runs 1 and 2 of the LHC. .
An attractive research area is the quantum mechanical oscillation between the particle and antiparticle states of neutrons, implying a coupled system of two mesons with different lifetimes. Phenomenology of Bs The system is of particular interest because it provides a sensitive probe to physics beyond the standard model. ABs Mesons vibrate at a frequency of about 3.×Ten12Hz, or about 9 times on average during lifetime, τ. In addition, heavy (ΓH.) and lights (ΓL.) mass eigenstates are expected. Lifetime measurements of CP-even Bs-decay mode is determined τL.= 1/ΓL..
The LHCb recently released new precise measurements of this parameter.s → J/ψη Decay selected from 5.7 fb–1 Run 2 of the data. This study shows a 2x improvement in accuracy over the previous run 1. Due to the combinatorial background, η Mesons by two-photon decay mode are a particular challenge for this analysis. Nevertheless, even the modest energy resolution of the calorimeter leads to relatively broad mass peaks that partially overlap the signal from B.0 → J/ψηDamping, competitive accuracy achieved. Leveraging modern machine learning techniques to reduce background and well-understood LHCb detectors, Bs →J/ψηcollapse was observed (Fig. 1), and τL. Extracted from a two-dimensional fit to mass and decay time.
result of analysis τL.= 1.445 ± 0.016 (stat) ± 0.008 (syst) ps, which is the most accurate measurement of this quantity.Combine this with B’s LHCb Run 1 studys →D.s+ D.s– attenuation mode, τL.= 1.437 ± 0.014 ps, which is the expected value of the standard model (τL.= 1.422 ± 0.013 ps) value inferred from the measured value Γs and ΔΓs in Bs →J/ψφ collapse.Better knowledge τL. Both are expected by considering the other CP-even Bs collapses into a final state containing η Also η’ Meson, B.s →D.s+ D.s– Dataset collected in run 2 and following run 3.