Measurement of the Masses and Widths of the $\Sigma_c(2455)^+$ and $\Sigma_c(2520)^+$ Baryons

TL;DR

This paper reports precise measurements of the masses and first intrinsic width measurements of the $\,Sigma_c(2455)^+$ and $\,Sigma_c(2520)^+$ baryons using a large data sample from the Belle detector, providing data to test quark models.

Contribution

First measurements of the intrinsic widths of the $\,Sigma_c(2455)^+$ and $\,Sigma_c(2520)^+$ baryons, along with improved mass measurements, using extensive data from the Belle experiment.

Findings

Mass differences and widths of $\,Sigma_c(2455)^+$ and $\,Sigma_c(2520)^+$ measured.

Widths determined for the first time with statistical and systematic uncertainties.

Results provide data to test quark structure models of these baryons.

Abstract

Using 980 ${\rm fb}^{-1}$ 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 $\Sigma_c(2455)^+$ and $\Sigma_c(2520)^+$ 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 $\Sigma_c$ states.