Constraining the High-Density Behavior of the Nuclear Equation of State through Kaon Production in Au+Au Collisions at 1–2 AGeV with the HADES Spectrometer
Keywords:
Kaon production, Au+Au collisions, High-density nuclear matterAbstract
The primary aim of this work was to measure kaon production cross-sections in Au+Au collisions at energies of 1 to 2 AGeV with the HADES spectrometer. The goal was to conclude an understanding of the high-density behavior of nuclear matter and limit the nuclear EOS, and even more precisely its symmetry energy term, at densities applicable to astrophysical settings such as neutron stars.
We carried out heavy-ion collisions with beam momenta between 1.0 and 2.0 AGeV. Detection and identification of kaon production were achieved through the HADES spectrometer, consisting of tracking detectors, time-of-flight systems, and calorimetry. Kaon candidates were classified on the basis of momentum and time-of-flight, and production cross-sections of kaons were determined after normalizing identified kaon yields to collision rate events. Correcting for detection acceptance and efficiencies, Monte Carlo simulations were utilized.
Kaon production cross-sections were discovered to increase with increased energy, 0.042 mb at 1.0 AGeV, 0.070 mb at 1.5 AGeV, and 0.092 mb at 2.0 AGeV. The results were compared with predictions of theoretical models such as the UrQMD, RMF, and Chiral Perturbation Theory models. The data were more accurately explained by the RMF and Chiral Perturbation Theory models, both of which demand a softer nuclear symmetry energy at high densities. Kaon production was systematically underestimated by the UrQMD model.
The experimental findings indicate that the high-density nuclear EOS is softer than previously anticipated, particularly for nuclear symmetry energy. It has significant implications in neutron star physics and puts stringent constraints to describe nuclear matter at extreme conditions more accurately. Kaon production is demonstrated to be a sensitive probe to check the high-density EOS and can be utilized to guide next-generation nuclear physics experiments.
