The study of hadronic rescattering on K^∗0 resonance yield in baryon-rich QCD matter

Abstract The effect of hadronic rescattering on K ∗0 resonance yield can be studied by measuring K ∗0 / K ratio as a function of centrality or multiplicity. This study investigates how the size of the system and the chemical composition (meson–meson versus meson–baryon interaction) of the matter formed in heavy-ion collisions impact the process of hadronic rescattering. It is shown that existing calculation of K ∗0 / K ratio, which considers the interaction of K ∗0 and K mesons with only light mesons in the hadronic medium (neglecting interactions with baryons), fails to explain the measured K ∗0 / K ratio at RHIC beam energy scan (BES) energies. To understand the multiplicity dependence of the K ∗0 / K ratio at RHIC BES and SPS energies ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msqrt> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">NN</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> </mml:math> &lt; 20 GeV), the ultra relativistic quantum molecular dynamics (UrQMD) model is employed. UrQMD calculations suggest that for a given multiplicity, K ∗0 / K is more suppressed in Au+Au collision at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msqrt> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">NN</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> </mml:math> = 7.7 GeV, compared to that in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msqrt> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>s</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="italic">NN</mml:mi> </mml:mrow> </mml:msub> </mml:mrow> </mml:msqrt> </mml:math> = 200 GeV. This is possibly because of formation different type of quantum chromodynamics medium at 200 and 7.7 GeV, and change in interaction cross-section between hadrons with change in particle type and energy.