= Squark-mediated proton decay
{title2=$\tau_p\sim m_{\widetilde q}^4/(|\lambda'\lambda''|^2m_p^5)$}
Simultaneous trilinear <baryon number> and <lepton number> violation permits a <squark> to connect the two interactions and induce a dimension-six <proton-decay operator>. Its coefficient is of order $\lambda'\lambda''/m_{\widetilde q}^2$. A dimensional decay-width estimate then gives $\Gamma_p\sim|\lambda'\lambda''|^2m_p^5/m_{\widetilde q}^4$, up to phase space and hadronic matrix elements. The flavor antisymmetry of $U^cD^cD^c$ matters: the two down-type flavor indices must differ. For example, $\lambda''_{112}$ and $\lambda'_{112}$ allow strange-squark exchange in $p\to e^+\pi^0$.
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