Physicists spot rare particle decay, opening window into matter's asymmetry
Researchers at CERN have detected an extremely uncommon subatomic decay process for the first time, revealing unexpected details about how matter behaves. The discovery could refine our understanding of fundamental forces and may eventually improve how scientists predict particle behavior in high-energy physics experiments.
Originaltitel: Observation of the Rare Baryonic Decay 𝐵<sup>+</sup> → 𝑝¯Λ and Measurement of its Weak Decay Parameter
<p>The first observation of the decay 𝐵+→𝑝¯Λ is presented using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The signal significance exceeds seven standard deviations. Using the 𝐵+ → 𝐾0S𝜋+ decay as a normalization channel, the branching fraction is measured and combined with previous LHCb results based on data collected at 7 and 8 TeV in 2011 and 2012, yielding ℬ(𝐵+→𝑝¯Λ)=(1.24±0.17±0.05±0.03)×10−7, where the first uncertainty is statistical, the second is systematic, and the third comes from the uncertainty on the branching fraction of the normalization channel. The 𝐵+ → 𝑝¯Λ weak decay parameter is measured to be 𝛼𝐵=0.87+0.26−0.29±0.09, indicating the presence of comparable S-wave and P-wave decay amplitudes.</p>