Nonleptonic two-body weak decays of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi mathvariant="normal">Λ</mml:mi><mml:mi>b</mml:mi></mml:msub></mml:math> in a modified MIT bag model

Abstract

We study the nonleptonic two-body weak decays of ${\mathrm{\ensuremath{\Lambda}}}_{b}$ by modifying the MIT bag model without introducing new parameters to construct the momentum eigenstates of the baryons. We find that the branching ratios of ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}{\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$, ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{K}^{\ensuremath{-}}$, $p{\ensuremath{\pi}}^{\ensuremath{-}}$, and $p{K}^{\ensuremath{-}}$ are $(4.5\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, $(3.4\ifmmode\pm\else\textpm\fi{}0.1)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$, $(5.0\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, and $(6.0\ifmmode\pm\else\textpm\fi{}0.7)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$, which are all consistent with the current experimental data, respectively. We also explore $P$ and $CP$ asymmetries for the decays of ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}p({\ensuremath{\pi}}^{\ensuremath{-}},{K}^{\ensuremath{-}})$. In particular, we obtain that the direct $CP$-violating rate asymmetries in ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${\mathrm{\ensuremath{\Lambda}}}_{b}^{0}\ensuremath{\rightarrow}p{K}^{\ensuremath{-}}$ are around $\ensuremath{-}4.4%$ and 6.7%, in comparison with $(\ensuremath{-}2.5\ifmmode\pm\else\textpm\fi{}2.9)%$ and $(\ensuremath{-}2.5\ifmmode\pm\else\textpm\fi{}2.2)%$ from the Particle Data Group in 2020, respectively.

Topics & Concepts