Fysik & material 3.7

Physicists unlock new decay pathways of rare heavy particles

Researchers at CERN have identified previously unobserved decay patterns in exotic particles called b-hadrons, confirming theoretical predictions about particle interactions. The findings refine the Standard Model of physics and could improve understanding of matter asymmetry in the universe—a fundamental gap in scientific knowledge with long-term implications for materials science and quantum technology development.

Originaltitel: Study of b-hadron decays to Λ+ch−h′− final states

Abstrakt

Decays of Ξ−b and Ω−b baryons to Λ+ch−h′− final states, with h−h′− being π−π−, K−π− and K−K− meson pairs, are searched for using data collected with the LHCb detector. The data sample studied corresponds to an integrated luminosity of 8.7 fb−1 of pp collisions collected at centre-of-mass energies √s = 7, 8 and 13 TeV. The products of the relative branching fractions and fragmentation fractions for each signal mode, relative to the B−→Λ+c¯¯¯pπ− mode, are measured, with Ξ−b→Λ+cK−π−, Ξ−b→Λ+cK−K− and Ω−b→Λ+cK−K− decays being observed at over 5 σ significance. The Ξ−b→Λ+cK−π− mode is also used to measure the Ξ−b production asymmetry, which is found to be consistent with zero. In addition, the B−→Λ+c¯¯¯pK− decay is observed for the first time, and its branching fraction is measured relative to that of the B−→Λ+c¯¯¯pπ− mode.

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