Observation of Two Narrow States Decaying into $\Xi_{c}^{+}\gamma$ and $\Xi_{c}^{0}\gamma$

TL;DR

This paper reports the first observation of two narrow charmed strange baryons decaying into specific photon and Xi_c states, measuring their mass differences and identifying them as symmetric partners of known baryons.

Contribution

First experimental observation and identification of two narrow charmed strange baryons decaying into Xi_c gamma, expanding understanding of baryon spectroscopy.

Findings

Observed signals interpreted as Xi_c' states

Measured mass differences of approximately 108 MeV/c^2

Identified these states as symmetric partners of known Xi_c baryons

Abstract

We report the first observation of two narrow charmed strange baryons decaying to $\Xi_c^+\gamma$ and $\Xi_c^0\gamma$, respectively, using data from the CLEO II detector at CESR. We interpret the observed signals as the $\Xi_c^{+\prime}(c{su})$ and $\Xi_c^{0\prime}(c{sd})$, the symmetric partners of the well-established antisymmetric $\Xi_c^+(c[su])$ and $\Xi_c^0(c[sd])$. The mass differences $M(\Xi_c^{+\prime})-M(\Xi_c^+)$ and $M(\Xi_c^{0\prime})-M(\Xi_c^0)$ are measured to be $107.8\pm 1.7\pm 2.5$ and $107.0\pm 1.4\pm 2.5 MeV/c^2$, respectively.