Pentaquark decay is suppressed by chirality conservation

Abstract

It is shown, that if the pentaquark ${\Theta }^{+}=uudd\bar{s}$ baryon can be represented by the local quark current ${\eta }_{\Theta }$, its decay ${\Theta }^{+}\to n{K}^{+}(p{K}^0)$ is forbidden in the limit of chirality conservation. The ${\Theta }^{+}$decay width $\Gamma$ is proportional to ${\alpha }_s^2<0|\bar{q}q|0{>}^2$, where $<0|\bar{q}q|0>$, $q=u,d,s$ is quark condensate, and, therefore, is strongly suppressed. Also the polarization operator of the pentaquark current with isospin 1 is calculated using the operator product expansion and estimation for it mass is obtained .

Comments: 4 pages, 1 fig, typos corrected