排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
The lowest-lying glueballs are investigated in lattice QCD using N_f = 2 clover Wilson fermions on anisotropic lattices. We simulate at two different and relatively heavy quark masses, corresponding to physical pion masses of mπ~938 MeV and 650 MeV. The quark mass dependence of the glueball masses has not been investigated in the present study. Only the gluonic operators built from Wilson loops are utilized in calculating the corresponding correlation functions. In the tensor channel, we obtain the ground state mass to be 2.363(39) GeV and 2.384(67)GeV at mπ~938 MeV and 650 MeV, respectively. In the pseudoscalar channel, when using the gluonic operator whose continuum limit has the form of ∈_ijkTrB_iD_jB_k, we obtain the ground state mass to be 2.573(55) GeV and 2.585(65) GeV at the two pion masses. These results are compatible with the corresponding results in the quenched approximation. In contrast, if we use the topological charge density as field operators for the pseudoscalar, the masses of the lowest state are much lighter(around 1 GeV) and compatible with the expected masses of the flavor singlet qq meson. This indicates that the operator ∈ijk TrBiDjBk and the topological charge density couple rather differently to the glueball states and qq mesons. The observation of the light flavor singlet pseudoscalar meson can be viewed as the manifestation of effects of dynamical quarks. In the scalar channel, the ground state masses extracted from the correlation functions of gluonic operators are determined to be around 1.4-1.5 GeV, which is close to the ground state masses from the correlation functions of the quark bilinear operators. In all cases, the mixing between glueballs and conventional mesons remains to be further clarified in the future. 相似文献
6.
7.
We investigate the behavior of the chiral condensate in lattice QCD at finite temperature and finite chemical potential. The study was done using two flavors of light quarks and with a series of β and ma at the lattice size 24×122×6. The calculation was done in the Taylor expansion formalism. We are able to calculate the first and second order derivatives of <ψψ> in both isoscalar and isovector channels. With the first derivatives being small, we find that the second derivatives are sizable close to the phase transition and that the magnitude of ψψ decreases under the influence of finite chemical potential in both channels. 相似文献
8.
Low-energy scattering of D ^*+ and D1^0 meson is studied using quenched lattice QCD with improved lattice actions on anisotropic lattices.The threshold scattering parameters,namely the scattering length a 0 and the effective range r 0,for the s-wave scattering in J P = 0 - channel are extracted: a 0 = 2.52(47) fm and r 0 = 0.7(1) fm.It is argued that,albeit the interaction between the two charmed mesons being attractive,it is unlikely that they can form a shallow bound state in this channel.Our calculation provides some useful information on the nature of the newly discovered resonance-like structure Z + (4430) by the Belle Collaboration. 相似文献
9.
Exactly solvable models are important in quantum physics. Usually, there are some underlying quantum dynamical algebras (QDA) inherit in these physical models. For instance, the QDA SU(1, 1) has been revealed in some important one-dimensional exactly solvable potentials, such as the harmonic oscillator, PSsehl-Teller potential, the radial Kratzer molecular potential, etc. However, the case for the one-dimensional Morse potential has not been studied in Ref. . Namely, whether the Morse potential possesses an QDA SU(1, 1) or not is still an open problem. 相似文献
10.
应用格点QCD理论对电荷涨落和夸克数密度敏感性进行了研究. 研究选取了
两个轻味夸克, 应用staggered作用量, 并选取了16×82×4格点. 对电荷涨落和夸克数密度敏感性在V=(2a)3~(8a)3(这里a=\kou\dfrac{1}{4T})区间进行了数值计算. 结果显示, 在相变温度以下的区域内, 上述参数对体积V具有依赖性, 这表明了可以通过对上述参数的研究来确定强子的尺度. 在高于相变温度的区域内, 对体积V没有表现出依赖性. 相似文献