Exploring the properties of the phases of QCD matter - research opportunities and priorities for the next decade

Heinz U, Sorensen P, Deshpande A, et al. Exploring the properties of the phases of QCD matter - research opportunities and priorities for the next decade. 2015.This document provides a summary of the discussions during the recent jointQCD Town Meeting at Temple University of the status of and future plans for theresearch program of the relativistic heavy-ion community. A list of compellingquestions is formulated, and a number of recommendations outlining the greatestresearch opportunities and detailing the research priorities of the heavy-ioncommunity, voted on and unanimously approved at the Town Meeting, arepresented. They are supported by a broad discussion of the underlying physicsand its relation to other subfields. Areas of overlapping interests with the"QCD and Hadron Structure" ("cold QCD") subcommunity, in particular therecommendation for the future construction of an Electron-Ion Collider, areemphasized. The agenda of activities of the "hot QCD" subcommunity at the TownMeeting is attached