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$SU(3)$ vs. $SU(3) \times SU(3)$ Breaking in Weak Hyperon Decays

Markus A. Luty·Martin White
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Abstract

We consider the predictions of chiral perturbation theory for $SU(3)$ breaking in weak semileptonic and $s$-wave nonleptonic hyperon decays. By defining an expansion sensitive only to $SU(3)$ breaking, we show that the leading corrections give rise to moderate corrections to $SU(3)$ relations ($\lsim 20\%$), even though the {\it chiral} symmetry $SU(3) \times SU(3)$ appears to be rather badly broken. This explains why $SU(3)$ fits to weak hyperon decays work well even though chiral-symmetry breaking corrections are large. Applying these $SU(3)$-breaking corrections to the analysis of the EMC data, we find that the predicted value of $\bra p\mybar sγ_μγ_5 s\ket p$ is reduced by $\simeq 35\%$, suggesting that the ``EMC effect'' may be less striking than commonly thought.

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Markus A. Luty, Martin White. 1993-04-24. $SU(3)$ vs. $SU(3) \times SU(3)$ Breaking in Weak Hyperon Decays. https://arxiv.org/abs/hep-ph/9304291

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