有限温度下轻介子的质量

研究有限温度下强子质量谱随温度的演化对于深入理解有限温量子色动力学和夸克胶子等离子体的性质至关重要,特别对它们的研究有助于人们确定QCD手征相变的阶和相变温度.线性σ模型是研究零温和有限温强子性质的重要有效场论模型之一,在U（2）×U（2）线性σ模型下,使用有限温场论的实时公式计算了轻介子σ、π、a、η的质量随温度变化的情况.计算结果表明,π、a、η介子的质量随着温度的升高而增加;σ介子的质量随温度的升高而下降.从质量谱上没有看到手征对称性恢复的迹象.

The masses of light mesons at finite temperature

Investigating the evolving of hadron masses with temperature is very important for us to un- derstand deeply the properties of Quantum Chromodynimics at finite temperature and quark-gluon plasma,especially the research is helpful to determining the order and critical temperature of the chiral phase transition in QCD. The linear a model and its extension are one of the important effective field theory models dealing with hadron properties at both zero and finite temperature. In this thesis, we investigate the temperature evolving of the masses of the light mesons σ、π、a and η using the real time finite temperature field theory in the frame of the U（2）×U（2） linear σ model. Our calculations show that the masses of π、a and π、a、η increase monotonically with increasing temperature, while the mass of σ decrease monotonically. No evidence of chiral symmetry restoration exits in the mass spectrum.