Measurement of the Masses and Widths of the ${\mathrm{\Sigma }}_c(2455{)}^{+}$ and ${\mathrm{\Sigma }}_c(2520{)}^{+}$ Baryons

Using 980 ${\mathrm{f}\mathrm{b}}^{-1}$ of data {collected} with the Belle detector operating at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we report the measurements of the masses, and the first measurements of the instrinsic widths, of the ${\mathrm{\Sigma }}_c(2455{)}^{+}$ and ${\mathrm{\Sigma }}_c(2520{)}^{+}$ charmed baryons. We find $M(\Sigma_c(2455)^+)-M(\Lambda_c^+) = 166.17\pm 0.05^{+0.16}{-0.07}\ {\rm MeV}/c^2$,$\Gamma(\Sigma_c(2455)^+) = 2.3 \pm 0.3 \pm 0.3\ {\rm MeV/c^2}$,$M(\Sigma_c(2520)^+)-M(\Lambda_c^+) = 230.9 \pm 0.5 ^{+0.5}{-0.1}\ {\rm MeV}/c^2$,and$\Gamma(\Sigma_c(2520)^+) = 17.2^{+2.3\ +3.1}_{-2.1\ -0.7}\ {\rm MeV}/c^2$, where the uncertainties are statistical and systematic, respectively. These measurements can be used to test models of the underlying quark structure of the ${\mathrm{\Sigma }}_c$ states.