Systematic Study on Precursory Phenomena of Chiral Phase Transition in Hadronic Matter

本项目的目的是系统地研究有限T和有限密度下手征跃迁和色超导（CSC）的特征性质和物理现象，并由此阐明实验验证它们的可能方法：（1）我们阐明了在非线性σ模型中可能的手征恢复如何影响σ和ρ介子通道中的强度函数。(2)We探索了利用（d，^3He）和（d，t）反应产生σ介子核的可能性。(3)We已经指出，深束缚π核中π的反常行为以及π或γ诱导2π产生中2m_π阈值附近强度函数的反常增强可以用π在核介质中的波函数重整化统一描述。(4)We证明了在全格点QCD模拟中可以存在质量与ρ介子大致简并的σ介子。(5)We已经表明，夸克谱可以大大修改，由于耦合的手征跃迁在有限T的软模。(6)We已经表明，矢量型相互作用可以在低温下修改相图，从而使QCD相图中出现另一个临界端点。（7）即使在远高于CSC临界温度的情况下，CSC的软化模式仍能存在并具有显著的强度。（8）CSC的软模影响了T_c附近但高于T_c的夸克性质，使夸克物质成为非费米液体，在夸克态密度中产生赝能隙。

The purposes of this project is to investigate systematically the characteristic properties and the precursory phenomena of the chiral transition and the color superconductivity(CSC) at finite T and density, and thereby elucidate the possible methods to verify them experimentally :(1)We have clarified how the possible chiral restoration affects the strength function in the sigma and the rho meson channels in a nonlinear sigma model.(2)We have explored the possibility to create the σ mesic nuclei using (d,^3He) and (d,t) reactions.(3)We have indicated that the anomalous behavior of the π in deeply bound pionic nuclei and also the anomalous enhancement of the strength function near the 2m_π threshold in π- or γ-induced 2π creations can be unifiedly described in terms of the wave function renormalization of the π in the nuclear media.(4)We have shown that the σ meson with a mass roughly degenerate with the rho meson can exist in the full Lattice QCD simulation.(5)We have shown that the quark spectra can be drastically modified due to the coupling with the soft mode of the chiral transition at finite T.(6)We have shown that the vector-type interaction can modify the phase diagram at low temperature so as to make another critical end point in the QCD phase diagram.(7)The precursory soft mode of the CSC can exist with a prominent strength even well above the critical temperature of the CSC.(8)The soft mode of the CSC affects the quark properties near but above Tc so that the quark matter may become a non-Fermi liquid, making a pseudogap in the density of states of the quarks.