Research on the quarkgluon plasma and its probes
Project/Area Number  09640350 
Research Category 
GrantinAid for Scientific Research (C)

Allocation Type  Singleyear Grants 
Section  一般 
Research Field 
素粒子・核・宇宙線

Research Institution  The University of Tokyo(1999) Kyoto University(19971998) 
Principal Investigator 
MATSUI Tetsuo The University of Tokyo, Graduate School of Arts and Sciences, Professor, 大学院・総合文化研究科, 教授 (00252528)

Project Period (FY) 
1997 – 1999

Project Status 
Completed(Fiscal Year 1999)

Budget Amount *help 
¥2,400,000 (Direct Cost : ¥2,400,000)
Fiscal Year 1999 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1998 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1997 : ¥1,100,000 (Direct Cost : ¥1,100,000)

Keywords  quarkgluon plasma / ultrarelativistic nucleusnucleus / chiral phase transition / J / ψ suppression / カイラル相転移 / Ψ抑圧 / クォーク・グルオン・プラズマ / 相対論的重イオン反応 
Research Abstract 
Research was conducted on signals of the quarkgluon plasma formation in ultrarelativistic nucleusnucleus collision, focusing on the dynamical process of the chiral phase transition and J/ ψ suppression by the onset of Debye screening in the plasma. As a quarkgluon plasma cools down, a phase transition is expected to occur associated with spontaneous breakdown of the (approximate) chiral symmetry. We studied the dynamics of the order parameter of this phase transition using the linear sigma model, an effective theory of QCD. We adopted the framework of the functional Schrodinger equation with variational ansatz for the wavefunctional. We generalized the classical planewave solutions of the nonlinear sigma model (the AnselmRyskin solutions) to include the effect of the quantum fluctuations by the method. We formulated a meanfield theory of the interacting quantum meson fields based on the HatreeBogoliubov method in the manybody problem and showed that our noncovariant functional Schrodinger equations can be transformed to a manifestly covariant form of KleinGordon type equations. Our solutions of collective isospin rotating modes of interacting meson fields was also extended to finite temperature using the Gaussian density matrices and the damping time of the modes was estimated by the linear response theory. The problem of J/ ψ suppression as a signal of the quarkgluon plasma was studied focusing on the interplay of a coherent effect such as the plasma screening of the binding potential of heavy quark and its antiparticle and an incoherent effect such as the scattering with individual plasma

Report
(4results)
Research Output
(15results)