Electromagnetic Decay of the $\Sigma^{0}(1385)$ to $\Lambda\gamma$

TL;DR

This study measures the electromagnetic decay width of the $ ext{Sigma}^0(1385)$ to $ ext{Lambda} ext{gamma}$, providing experimental data that challenges existing theoretical predictions and enhances understanding of hyperon decays.

Contribution

First experimental measurement of the decay width ratio for $ ext{Sigma}^0(1385)$ to $ ext{Lambda} ext{gamma}$, offering new data to test hyperon decay models.

Findings

Decay width ratio $ ext{Sigma}^0(1385) o ext{Lambda} ext{gamma}$ / $ ext{Lambda} ext{pi}^0$ is 1.42 ± 0.12 (stat) with systematic uncertainties.

Measured ratio exceeds most theoretical predictions by factors of 1.5 to 3.

Calculated the partial width and electromagnetic transition magnetic moment for the decay.

Abstract

The electromagnetic decay $\Sigma^0(1385) \to \Lambda \gamma$ was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility. A real photon beam with a maximum energy of 3.8 GeV was incident on a proton target, producing an exclusive final state of $K^+\Sigma^{*0}$. We report the decay widths ratio $\Sigma^0(1385) \to \Lambda\gamma$/ $\Sigma^0(1385) \to \Lambda\pi^0$ = $1.42 \pm 0.12(\text{stat})_{-0.07}^{+0.11}(\text{sys})$%. This ratio is larger than most theoretical predictions by factors ranging from 1.5-3, but is consistent with the only other experimental measurement. From the reported ratio we calculate the partial width and electromagnetic transition magnetic moment for $\Sigma^0(1385) \to \Lambda\gamma$.