Probing hot and dense nuclear matter with K*, K¯* vector mesons

Andrej Ilner,Christina Markert,Elena Bratkovskaya,Justin Blair,Daniel Cabrera

doi:10.1103/physrevc.99.024914

Abstract

We investigate probing the hot and dense nuclear matter with strange vector mesons ($K^*, \bar{K}^*$). Our analysis is based on PHSD which incorporates partonic and hadronic dof and describes the full dynamics of HICs. This allows to study the $K^*$ and $\bar{K}^*$ meson formation from the QGP and the in-medium effects related to the modification of their properties during the propagation in dense and hot matter. We employ relativistic Breit-Wigner spectral functions for the $K^*,\bar{K}^*$ mesons with self-energies obtained from a G-matrix approach to study the role of in-medium effects on the $K^*$ and $\bar{K}^*$ meson dynamics in HIC from FAIR/NICA to LHC energies. According to our analysis most of the final $K^*/\bar{K}^*$s, that can be observed experimentally, are produced during the late hadronic phase and stem dominantly from the $K (\bar{K}) + \pi \to K^*(\bar{K}^*)$ formation channel. The amount of $K^*/\bar{K}^*$s originating from the QGP channel is comparatively small even at LHC energies and such $K^*/\bar{K}^*$s can hardly be reconstructed experimentally due to the rescattering of final pions and (anti-)kaons. This mirrors the results from our previous study on the strange vector-meson production in HICs at RHIC energies. The influence of the in-medium effects on the dynamics of the $K^*/\bar{K}^*$ is rather small since they are mostly produced at low baryon densities. Additional cuts on the shape of the observed signal and the range of the invariant mass region of the $K^*/\bar{K}^*$ also affect the final spectra. We demonstrate that the $K^*/\bar{K}^*$ in-medium effects are more visible at lower beam energy, e.g. FAIR/NICA and BES RHIC energies, where the production of $K^*/\bar{K}^*$s occurs at larger baryon densities. Finally, we present the experimental procedures to extract information on the in-medium masses and widths by fitting final mass spectra at LHC energies.

Highlights

The properties of hot and dense matter under extreme conditions, the origin of the phase transition from hadronic to partonic matter, and the formation of the quark-gluon plasma (QGP) are the subjects of extensive theoretical and experimental studies in the last decades
Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory (BNL), and the Super-Proton Synchrotron (SPS) and the Large Hadron Collider (LHC) at the Conseil Européen pour la Recherche √Nucléaire (CERN) which cover the range in invariant energy sNN from a few GeV at SIS to ∼5 TeV at LHC
There we have investigated the different mechanisms for the K∗/K∗ production and have shown that most of the K∗/K∗ measured experimentally at RHIC energies originate from π + K (K ) annihilation and overshine the direct production from the QGP which makes it quite difficult to use the K∗/K∗ as a probe of the late partonic phase

Summary

Introduction

The properties of hot and dense matter under extreme conditions, the origin of the phase transition from hadronic to partonic matter, and the formation of the quark-gluon plasma (QGP) are the subjects of extensive theoretical and experimental studies in the last decades. Such conditions— realized in nature during the “big bang” at the beginning of our universe—can be achieved nowadays in the laboratory in the collisions of heavy ions. Two further accelerators are under construction—the Facility for Antiproton and Ion Research (FAIR) as well as the Nuclotron-based Ion Collider fAcility (NICA)—which will become operational in the years

Objectives

Methods

Results