# 55. International Winter Meeting on Nuclear Physics

23-27 January 2017
Bormio, Italy
Europe/Berlin timezone

## First observation of $\Sigma^{0}$ production in proton induced reactions on a nuclear target*

25 Jan 2017, 17:20
20m
Bormio, Italy

#### Bormio, Italy

Short Contribution

### Speaker

Mr Tobias Kunz (Technische Universität München)

### Description

We have studied the production of neutral $\Sigma^{0}$ baryons in the nuclear reaction p + Nb at an incident proton energy $E_{kin}$ = 3.5 GeV. The measurement has been performed with the HADES experiment setup at GSI, Darmstadt. $\Sigma^{0} \rightarrow \Lambda^{0} \gamma$ decays were identified via the charged decay $\Lambda^{0} \rightarrow p \pi^{-}$ coincident to $e^{+}e^{-}$ pairs from external gamma conversion. Experimental details, analysis procedures and background determination are presented. An observed total of about 250 candidate events is used to determine the $\frac{\Lambda + \Sigma}{\Sigma}$ production ratio. The obtained numbers and spectra are compared to predictions from transport model calculations and are discussed in the context of thermal particle production in nuclear fireballs. *Supported by the Excellence Cluster Universe

### Primary author

Mr Tobias Kunz (Technische Universität München)

 Slides