Seq. Number (TBA ) Research Plan at RIKEN CC-J Date: 04/11/2010 (DD/MM/YY) To: the Planning and Coordination Office of RIKEN CC-J Reseach Subject : Search for a signal of chiral symmetry restoration in hot QCD matter (PHENIX official or not : no ) Person responsible for this reserch: Name : Yosuke Watanabe Tel/Fax : 03-5841-7642/03-5841-4236 E-mail : yosuke-at-nucl.phys.s.u-tokyo.ac.jp Person responsible for the job submission: Name : Yosuke Watanabe Tel/Fax : E-mail : Other collabrators in this research subject: Name : tel/Fax: E-mai: Summary of this research (5-10 lines) Chiral symmetry is said to restore in the matter generated at RHIC. For the study of the chiral properties, vector mesons, such as ϕ, ω and ρ are interesting because the restoration of chiral symmetry at high temperature may modify their mass and width. Here, the measurements with lepton decays are essential, since leptons do not interact with the medium and carry direct information about conditions and properties of the medium. However, large background in electron pairs due to π0 Dalitz decay and γ conversion make the measurement difficult in the past PHENIX data. In this year, Hadron Blind Detector (HBD) was newly installed to reject those backgrounds and was successfully operated. The chiral properties of the matter will be investigated in detail using the invariant mass spectra with improved signal-to-background ratio. Estimated CPU time required : hours (with Pentium III 1GHz) Estimated disk space usage required : 1,000 GB Estimated HPSS space usage required : 1,000 GB HPSS band width for above estimate : MB/s Target date for completion (cpu) : 31/ 3 / 2013 (DD/MM/YY) (disk): 31/ 3 / 2013