Measurement of charged pions in 12C + 12C collisions at 1A GeV and 2A GeV with HADES

TL;DR

This study measures charged pion production in 12C + 12C collisions at 1A and 2A GeV using HADES, providing new large-angular range data and comparing results with transport models and previous experiments.

Contribution

First large-angular range measurement of charged pion emission in 12C + 12C collisions at these energies, enhancing understanding of pion production mechanisms.

Findings

Pion yields and distributions are consistent with transport model predictions.

Observed anisotropy in pion emission patterns.

Data extends the angular coverage of pion production measurements.

Abstract

We present the results of a study of charged pion production in 12C + 12C collisions at incident beam energies of 1A GeV and 2A GeV using the HADES spectrometer at GSI. The main emphasis of the HADES program is on the dielectron signal from the early phase of the collision. Here, however, we discuss the data with respect to the emission of charged hadrons, specifically the production of pi+- mesons, which are related to neutral pions representing a dominant contribution to the dielectron yield. We have performed the first large-angular range measurement of the distribution of pi+- mesons for the 12C + 12C collision system covering a fairly large rapidity interval. The pion yields, transverse-mass and angular distributions are compared with calculations done within a transport model, as well as with existing data from other experiments. The anisotropy of pion production is systematically analyzed.