Chiral transition at high temperature and density and the σ-meson in nuclear medium
| Project/Area Number |
12640296
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KUNIHIRO Teiji Yukawa Institute for Theoretical Physic, Kyoto University, Professor, 基礎物理学研究所, 教授 (20153314)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Chiral Symmetry / QCD / Sigma meson / Renormalization Group / Transport Equations / Chiral Transition / 運動学的方程式 / TDGL |
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| Research Abstract |
(1) We have shown that partial restoration of chiral symmetry in nuclear medium induces a softening in the spectral function in the I = J = 0 channel, I.e., the σ-meson channel, irrespective of the linear or nonlinear representation of chiral symmetry; the softening can account for the experimental data by CHAOS group. The restoration of chiral symmetry is represented by a 4pi-NN vertex in the nonlinear chiral model that has been taken into account in the previous calculations in the literature.
(2) Apart from 7r-nucleus reactions, we have shown (d, ^3He) and (d, t) reactions are interesting as a probe to explore partial restoration in heavy nuclei because they may produce the σ-mesic nuclei.
(3) To examine whether the effective equation to describe the disoriented chiral condensate (DCC) is diffusion- or wave-equation type, we tried to deduce the time-dependent Ginzburg-Landau equation (TDGL) consistently by applying the derivative expansion. We have identified the divergence inherent in the derivative expansion due to the Landau damping a secular term familiar in the perturbation series of solutions of differential equations. Applying the so called the renormalization-group (RG) method, we have successfully obtained the resumed coefficients. It is underway to examine the resultant evolution equation has to do with TDGL.
(4)Applying the RG method, we have given a unified and general theory for deriving kinetic and transport equations from the microscopic, equations including field theories.
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Report
(3 results)
Research Products
(9 results)
