CP violation with beautiful baryons

  • Isard Dunietz


CP violation can be studied in modes of charmed or bottom baryons when a decay process is compared with its charge-conjugated partner. It can show up as a rate asymmetry and in a study of other decay parameters. Neither tagging nor time-dependences are required to observeCP violation with modes of baryons, in contrast to the conventionalB0 modes. Numerous modes of bottom baryons have the potential to show largeCP-violating effects within the Standard Model. Those effects can be substantial for modes with aD0, which is seen in a final state that can also be fed from a\(\bar D^0 \). For instance, a comparison of theΛbΛCP0 with the\(\bar \Lambda _b \to \bar \Lambda D_{CP}^0 \) process can show sizeableCP violation. HereDCPo denotesCP eigenstates ofD0, which occur at a few percent. Six related processes, such asΛbΛD0,\(\Lambda _b \to \Lambda \bar D^0 \),ΛbΛCP0, and their charge-conjugated counterparts, can extract ϕ, which is the most problematic angle of the unitarity triangle and which is conventionally probed with theBs→ρ0KS asymmetry. HereD0 andD−0 are identified by their charged kaon or lepton. We predictB(ΛbΛD0)∼10−5, thusB(ΛbΛCP0)∼10−7. Under favourable circumstances,CP violation can occur at the few tens of percent level. Thus 102–103ΛbΛCP0 decays start probing ϕ. Tables list many additional modes with typical branching ratios at the 10−5–10−6 level, with large detection efficiencies (in contrast to theDCP0), and with potentially largeCP-violating effects, such as Ξb0→ΛΨ, Λϕ, ΛK*0; Ξb→ΛK(*)−, ΞKs, ΞK*0, Ωb→Ξφ, Ξρ0, ΛK(*)−, ΩKs, ΩK*0.


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Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Isard Dunietz
    • 1
  1. 1.Theory DivisionCERNGeneva 23Switzerland

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