Improved Tests of Relations for Baryon Isomultiplet Splittings

Abstract

The least well-known octet baryon mass is $M_{{\Xi }^0}=1314.9\pm 0.6$ MeV. The prospect of an improved measurement of its mass by the KTeV experimental program at Fermilab, and opportunities for improvements in charged and excited hyperon and $\Delta$ mass measurements, makes it timely to re-examine descriptions of isospin splittings in baryons containing light quarks. It is possible by examining such relations as the Coleman-Glashow relation $M_n-M_p+M_{{\Xi }^{-}}-M_{{\Xi }^0}=M_{{\Sigma }^{-}}-M_{{\Sigma }^{+}}$ to distinguish between those models making use of one- or two-body effects involving quarks and those involving genuine three-body effects. A hierarchy based on an expansion in $1/N_c$, where $N_c$ is the number of quark colors, is useful in this respect. The present status of other quark-model mass relations involving $\Lambda -{\Sigma }^0$ mixing and the baryon decuplet is also noted, and the degree to which one can determine parameters such as quark mass differences and individual electromagnetic contributions to splittings is discussed.

16 pages, LaTeX, no figures. Revised February 1998: further text and references

References in corpus (1)

• Remarks on the Delta(+) mass

Cited by in corpus (17)

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• First Observation of Heavy Baryons Σ_b and Σ_b^*
• A Theory of X and Z Multiquark Resonances
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• Mass splittings in ${\Sigma }_b$ and ${\Sigma }_b^{\ast }$
• The X(3872) tetraquarks in B and B_s decays
• Isospin Mass Splittings of Baryons in Potential Models
• Screening of quark charge and mixing effects on transition moments and M1 decay widths of baryons
• First Observation of Bottom Baryon Sigma_b States at CDF
• Status of isospin splittings in mesons and baryons
• Predictions for masses of bottom baryons
• Electromagnetic corrections to baryon masses
• Measurements of the Sigma_c^0 and Sigma_c^{++} Mass Splittings
• Delta isobar masses, large N_c relations, and the quark model
• Possibility of narrow resonances in nucleon-nucleon channels
• Properties of Heavy B Hadrons
• The u-d quark mass difference and nuclear charge symmetry breaking