Pentaquarks in the $\bar{10}_F$- and ${10_F}$-plets

Abstract

We discuss the mass splittings of the pentaquark $10_F$-, and ${\bar {10}}_F$-plet due to the quark mass differences, as well as %We discuss the $10_F$-plet's median mass relative to that of the ${\bar {10}}_F$% -plet of pentaquarks for both the flavour-spin and the colour-spin hyperfine interactions, and for both parities of the pentaquark ground states. We show that the colour-spin interaction leads to degenerate $10_F$- and ${\bar {10}}_F$-plets when the parity is even, and a median mass splitting of 75 MeV for odd parity. The flavour-spin interaction leads to $10_{F}-{\bar {10}}_F$ median mass splittings of 200 MeV and 40 MeV, for even and odd parities, respectively. We display mass relations between $10_F$- and ${\bar {10}}_F$-plets and analyze the presently known baryon resonances in this light.