Speaker
Description
Constituent quark number scaling has been proposed as one of the key signatures of a QGP phase. The flow scaling arises from a quark coalescence picture relevant at intermediate transverse momenta. While at collision energies above 7.7 GeV the NCQ scaled elliptic flow of baryons and mesons aligns very well, the scaling breaks between 4.5 and 3.0 GeV as evidenced by recent STAR measurements. At these energies the shadowing effect induced by the bypassing spectator leads to tremendous absorption and thus one cannot distinguish between quark coalescence from the QGP with shadowing from a purely hadronic phase with shadowing. Here I develop a new method to disentangle the shadowing effect of different hadron species and reconstruct the anisotropy of the emission source. The method is shown to reliably reconstruct the emission anisotropy in UrQMD calculations of the elliptic flow of baryons, mesons as well as light nuclei and hypernuclei. This will allow the STAR, HADES and the upcoming CBM experiment to unshadow their flow measurements and decipher whether NCQ scaling is present in this energy regime, thus making it relevant for the critical point search.