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$\mathit CP$ AND $\mathit T$ VIOLATION PARAMETERS

Measured values of the triple-product asymmetry parameters, odd under time-reversal, are defined as ${{\mathit A}}_{c(s)}({{\mathit \Lambda}}/{{\mathit \phi}}$) = (${{\mathit N}}{}^{+}_{c(s)}$ $−$ ${{\mathit N}}{}^{−}_{c(s)}$) $/$ (sum) where ${{\mathit N}}{}^{+}_{c(s)}$, ${{\mathit N}}{}^{−}_{c(s)}$ are the number of ${{\mathit \Lambda}}$ or ${{\mathit \phi}}$ candidates for which the cos(${{\mathit \Phi}}$) and sin(${{\mathit \Phi}}$) observables are positive and negative, respectively. Angles cos(${{\mathit \Phi}}$) and sin(${{\mathit \Phi}}$) are defined as in LEITNER 2007 .

a$_{CP}$( ${{\mathit \Lambda}_{{b}}^{0}}$ $\rightarrow$ ${{\mathit p}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ )

INSPIRE   PDGID:

S040A08

Observable calculated as half of the difference between triple products for ${{\mathit \Lambda}_{{b}}^{0}}$ and ${{\overline{\mathit \Lambda}}_{{b}}^{0}}$, which is sensitive to $\mathit CP$ violation.

VALUE (%) DOCUMENT ID TECN  COMMENT $-0.7$ $\pm0.7$ $\pm0.2$ 1 AAIJ 2020 AB LHCB ${{\mathit p}}{{\mathit p}}$ at 7, 8, 13 TeV • • We do not use the following data for averages, fits, limits, etc. • • $1.15$ $\pm1.45$ $\pm0.32$ 2 AAIJ 2017 H LHCB Repl. by AAIJ 2020AB 1  Used both triple product asymmetries and the unbinned energy test method. 2  Measured over full phase space of the decay.

Conservation Laws:

$\mathit CP$ INVARIANCE

References:

AAIJ 2020AB PR D102 051101 Search for $C\!P$ violation and observation of $P$ violation in $\Lambda_b^0 \to p \pi^- \pi^+ \pi^-$ decays AAIJ 2017H NATP 13 391 Measurement of Matter-Antimatter Differences in Beauty Baryon Decays

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