Measurement of $K^*(892)^0$ and $K^0$ mesons in Al+Al collisions at 1.9$A$ GeV

TL;DR

This study reports new measurements of $K^*(892)^0$ and $K^0$ mesons in Al+Al collisions at 1.9A GeV, providing insights into sub-threshold production and in-medium interactions of strange particles.

Contribution

The paper presents the first complete measurement of $K^*(892)^0$ and $K^0$ production in Al+Al collisions at this energy, including the yield ratio and comparison with theoretical models.

Findings

The $K^*(892)^0$ / $K^0$ yield ratio is 0.0315±0.006 (stat.)±0.012 (syst.)

Measured ratio agrees with UrQMD model predictions

Results inform on in-medium $K^+$ - $\pi^-$ fusion cross section.

Abstract

New measurement of sub-threshold $K^*(892)^0$ and $K^0$ production is presented. The experimental data complete the measurement of strange particles produced in Al+Al collisions at 1.9$A$ GeV measured with the FOPI detector at SIS/GSI. The $K^*(892)^0$ / $K^0$ yield ratio is found to be $0.0315\pm 0.006 (\mathrm{stat.})\pm 0.012 (\mathrm{syst.})$ and is in good agreement with the UrQMD model prediction. These measurements provide information on in-medium cross section of $K^+$ - $\pi^-$ fusion which is the dominant process on sub-threshold $K^*(892)^0$ production.