${{\boldsymbol \Sigma}}$ BARYONS
($\boldsymbol S$ = $-1$, $\boldsymbol I$ = 1)
${{\mathit \Sigma}^{+}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit u}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{0}}$ = ${\mathit {\mathit u}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$, ${{\mathit \Sigma}^{-}}$ = ${\mathit {\mathit d}}$ ${\mathit {\mathit d}}$ ${\mathit {\mathit s}}$
INSPIRE search

${{\boldsymbol \Sigma}{(1385)}}$ $I(J^P)$ = $1(3/2^{+})$

Discovered by ALSTON 1960 . Early measurements of the mass and width for combined charge states have been omitted. They may be found in our 1984 edition Reviews of Modern Physics 56 S1 (1984). We average only the most significant determinations. We do not average results from inclusive experiments with large backgrounds or results which are not accompanied by some discussion of experimental resolution. Nevertheless systematic differences between experiments remain. (See the ideograms in the Listings below.) These differences could arise from interference effects that change with production mechanism and/or beam momentum. They can also be accounted for in part by differences in the parametrizations employed. (See BORENSTEIN 1974 for a discussion on this point.) Thus BORENSTEIN 1974 uses a Breit-Wigner with energy-independent width, since a ${\mathit P}{\mathrm -wave}$ was found to give unsatisfactory fits. CAMERON 1978 uses the same form. On the other hand HOLMGREN 1977 obtains a good fit to their ${{\mathit \Lambda}}{{\mathit \pi}}$ spectrum with a ${\mathit P}{\mathrm -wave}$ Breit-Wigner, but includes the partial width for the ${{\mathit \Sigma}}{{\mathit \pi}}$ decay mode in the parametrization. AGUILAR-BENITEZ 1981D gives masses and widths for five different Breit-Wigner shapes. The results vary considerably. Only the best-fit ${\mathit S}{\mathrm -wave}$ results are given here.
${{\boldsymbol \Sigma}{(1385)}}$ POLE POSITIONS
${{\mathit \Sigma}{(1385)}^{+}}$ REAL PART
${{\mathit \Sigma}{(1385)}^{+}}$ $−$IMAGINARY PART
${{\mathit \Sigma}{(1385)}^{-}}$ REAL PART
${{\mathit \Sigma}{(1385)}^{-}}$ $−$IMAGINARY PART
${{\boldsymbol \Sigma}{(1385)}}$ MASSES
${{\mathit \Sigma}{(1385)}^{+}}$ MASS   $1382.80 \pm0.35$ MeV (S = 1.9)
${{\mathit \Sigma}{(1385)}^{0}}$ MASS   $1383.7 \pm1.0$ MeV (S = 1.4)
${{\mathit \Sigma}{(1385)}^{-}}$ MASS   $1387.2 \pm0.5$ MeV (S = 2.2)
${\mathit m}_{{{\mathit \Sigma}{(1385)}^{-}}}–{\mathit m}_{{{\mathit \Sigma}{(1385)}^{+}}}$
${\mathit m}_{{{\mathit \Sigma}{(1385)}^{0}}}–{\mathit m}_{{{\mathit \Sigma}{(1385)}^{+}}}$
${\mathit m}_{{{\mathit \Sigma}{(1385)}^{-}}}–{\mathit m}_{{{\mathit \Sigma}{(1385)}^{0}}}$
${{\boldsymbol \Sigma}{(1385)}}$ WIDTHS
${{\mathit \Sigma}{(1385)}^{+}}$ WIDTH   $36.0 \pm0.7$ MeV 
${{\mathit \Sigma}{(1385)}^{0}}$ WIDTH   $36 \pm5$ MeV 
${{\mathit \Sigma}{(1385)}^{-}}$ WIDTH   $39.4 \pm2.1$ MeV (S = 1.7)
$\Gamma_{1}$ ${{\mathit \Lambda}}{{\mathit \pi}}$ $(87.0 \pm{1.5})\%$208
$\Gamma_{2}$ ${{\mathit \Sigma}}{{\mathit \pi}}$ $(11.7\pm{1.5})\%$129
$\Gamma_{3}$ ${{\mathit \Lambda}}{{\mathit \gamma}}$ $(1.25^{+0.13}_{-0.12})\%$241
$\Gamma_{4}$ ${{\mathit \Sigma}^{+}}{{\mathit \gamma}}$ $(7.0\pm{1.7})\times 10^{-3}$180
$\Gamma_{5}$ ${{\mathit \Sigma}^{-}}{{\mathit \gamma}}$ $<2.4\times 10^{-4}$CL=90%173
$\Gamma_{6}$ ${{\mathit N}}{{\overline{\mathit K}}}$ -1