有限体积内的K-π相互作用和K^＊共振态

K-π interaction in finite volume and the K^＊ resonance

为了找到一种获得K-π相移的有效方法,并从格点计算得到的能级中获取K*介子的性质,首先使用手征幺正理论研究了有限体积中的P波K-π相互作用.这种方法曾在无限空间中成功地应用于计算K-π相移.然后用这种方法计算得到作为立方体盒子尺寸和π介子质量的函数的P波K-π散射振幅的能级;并计算了K-π散射的相移以及基于该结果的K*介子的物理性质.最后,为了和格点量子色动力学(QCD)计算结果进行比较,又在π介子取非物理质量时计算得到了K*介子的能级.比较表明:文中方法与格点QCD得到的结果基本一致.当介子能量为266 Me V时,本文方法得到的两个能级分别为924.0 Me V和1 483.0 Me V,其结果与格点QCD得到的915.6 Me V和1 522.3 Me V的两个能级符合得很好.

Firstly,the K-π interaction in P-wave in a finite volume using the chiral unitary approach was studied,to find an efficient strategy to obtain K-π phase shifts and thus the K^＊meson properties from energy levels could be obtained in lattice calculations. This method has been applied to provide K-π shifts in infinite space very successfully. Secondly,the energy levels,which are functions of the cubic box size and the pion mass,were evaluated,and the K-π phase shifts were evaluated based on the physical properties of K^＊meson.Finally,in order to compare with the lattice quantum chromodynamics（ QCD） results,non-physical pion masses were adopted to calculate energy levels of the K^＊meson. Comparison shows that results from approach mentioned above agree well with those from lattice QCD： using pion mass 266 Me V,we obtain two energy levels,924. 0 Me V and 1 483. 0 Me V respectively,which accord well with the lattice QCD results,915. 6 Me V and 1 522. 3 Me V respectively.