Fysik & material 3.1

Physicists discover rare particle decays that could reshape matter theory

Researchers at CERN have observed three previously unseen decay patterns of exotic particles called B mesons, filling gaps in the standard model of physics. The discovery could help scientists understand why matter behaves differently than antimatter—a question with implications for everything from particle detector design to fundamental physics validation.

Originaltitel: Observation of B+c → Dh+h- Decays

Abstrakt

Searches are presented for B+c → Dh+h- decays, where D is a charmed meson and h± is a charged pion or kaon, using pp collision data collected by the LHCb experiment corresponding to an integrated luminosity of 9 fb-1. The decays B+c → D+K+π-, B+c → D*+K+π-, and B+c → D+sK+K- are observed for the first time. Their branching fractions, expressed as ratios relative to that of the B+c → B0sπ+ decay, are determined to be R(B+c → D+K+π-) = (1.96±0.23±0.08± 0.10) x 10-3, R(B+c → D*+K+π-) = (3.67±0.55±0.24±0.20) x 10-3, R(B+c → D+sK+K- = (1.61±0.35±0.13±0.07) x 10-3), where the first uncertainty is statistical, the second is systematic, and the third is due to the limited precision on the D-meson branching fractions. The decay channels proceed primarily through excited K0 or D0 resonances or Φ mesons, and open a new avenue for studies of charge-parity violation in beauty mesons.

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