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arXiv 0707.0399nucl-th
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非相对论组分夸克模型中的低位UD反S反S组态

Low-lying ud anti-s anti-s configurations in a non-relativistic constituent quark model

W. L. Wang, F. Huang, Z. Y. Zhang, Y. W. Yu, F. Liu

摘要:

在非相对论组分夸克模型中,用变分法计算了自旋宇称J^P=0^+、1^+和2^+的低位等夸克组态和等矢量ud反s反s组态的能量.研究了夸克-夸克相互作用势中包括s-通道相互作用在内的各个部分的贡献,并考察了不同形式的禁闭势的影响。模型参数的确定方法与我们以前的工作相同,它们仍然能满意地描述核子-核子散射相移和超子-核子截面。s-通道相互作用的参数由K和K^* 介子的质量决定,尺寸参数取两个可能的值。当取与重子相同时,数值结果表明,所有ud反s反s组态的质量都大于相应的介子-介子阈值。但当K和K^* 介子的尺寸参数调整到小于重子的尺寸参数时,发现I=0,J^P=1^+的ud反s反s组态低于K^*K^* 阈值,而且该态的KK^* 分量很小,与KK^* 之间的相互作用矩阵元也相对较小,因此,它与KK^* 通道的耦合将很弱,它可能被认为是一个可能的四夸克候选者。

英文摘要:

The energies of the low-lying isoscalar and isovector ud anti-s anti-s configurations with spin-parity J^P=0^+, 1^+, and 2^+ are calculated in a non-relativistic constituent quark model by use of the variational method. The contributions of various parts of the quark-quark interacting potentials including the s-channel interaction are investigated, and the effect of different forms of confinement potential is examined. The model parameters are determined by the same method as in our previous work, and they still can satisfactorily describe the nucleon-nucleon scattering phase shifts and the hyperon-nucleon cross sections. The parameters of the s-channel interaction are fixed by the masses of K and K^* mesons, for which the size parameter is taken to be two possible values. When it is chosen as the same as baryons', the numerical results show that the masses of all the ud anti-s anti-s configurations are higher than the corresponding meson-meson thresholds. But when the size parameter for the K and K^* mesons is adjusted to be smaller than that for the baryons, the ud anti-s anti-s configuration with I=0 and J^P=1^+ is found to lie lower than the K^*K^* threshold, furthermore, this state has a very small KK^* component and the interaction matrix elements between this state and KK^* is comparatively small, thus its coupling to the KK^* channel will consequently be weak and it might be regarded as a possible tetraquark candidate.

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