Time: 2:30 pm, Sept. 18, Friday

Location : Room 9409

Speaker:Daniel Cebra, Professor of Physics at UC Davis

Title: What we can learn from a Fixed Target Program at STAR

Abstract:

The creation of a partonic state of QCD matter has been demonstrated in relativistic heavy ion collisions at RHIC and at the LHC. Lattice QCD has demonstrated that, at the highest collision energies, there is a cross-over phase transition that occurs as the partonic quark-gluon plasma cools to form a hot hadronic gas. However, as we raise the baryon chemical potential of the medium by scanning the beam to lower collision energies,we hope to find evidence of a region of the QCD phase diagram that has
a first-order phase transition and a critical end-point. The first RHIC Beam Energy Scan (BES-I) found evidence consistent with these features,however more studies are needed and a follow-up scan is scheduled for 2019 and 2020 (BES-II). This talk explores the possibility of extending the reach of the BES-II program by adding an internal fixed target. The program will cover the center-of-mass energy range from 3.0 to 7.7 GeV. Collisions in this energy range form hot dense hadronic systems which are mostly likely
below the onset of deconfinement. I will review the results of tests that have been done over the past few years to demonstrate the feasibility of this fixed target program. I will also indicate the physics that could be added to the BES program by including a fixed target program.