Measurements of the Sigma_c^0 and Sigma_c^{++} Mass Splittings

TL;DR

This paper reports precise measurements of the mass differences between Sigma_c^0, Sigma_c^{++}, and Lambda_c^+ baryons using data from the FOCUS experiment, providing insights into isospin mass splittings in charmed baryons.

Contribution

The study presents the first high-precision measurements of Sigma_c^0 and Sigma_c^{++} mass splittings relative to Lambda_c^+ using photoproduction data.

Findings

Measured M(Sigma_c^0 - Lambda_c^+) = 167.38 +/- 0.21 +/- 0.13 MeV/c^2

Measured M(Sigma_c^++ - Lambda_c^+) = 167.35 +/- 0.19 +/- 0.12 MeV/c^2

Isospin mass splitting M(Sigma_c^++ - Sigma_c^0) = -0.03 +/- 0.28 +/- 0.11 MeV/c^2

Abstract

Using a high statistics sample of photoproduced charmed particles from the FOCUS experiment at Fermilab (FNAL-E831), we measure the mass splittings of the charmed baryons Sigma_c^0 and Sigma_c^{++}. We find M(Sigma_c^0 - Lambda_c^+) = 167.38 +/- 0.21 +/- 0.13 MeV/c^2 and M(Sigma_c^++ - Lambda_c^+) = 167.35 +/- 0.19 +/- 0.12 MeV/c^2 with samples of 362 +/- 36 and 461 +/- 39 events, respectively. We measure the isospin mass splitting M(Sigma_c^++ - Sigma_c^0) to be -0.03 +/- 0.28 +/- 0.11 Mev/c^2. The first errors are statistical and the second are systematic.