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arXiv 1302.6938hep-ph
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具有重夸克对称性的隐魅N和Delta共振

Hidden charm N and Delta resonances with heavy-quark symmetry

C. Garcia-Recio, J. Nieves, O. Romanets, L. L. Salcedo, L. Tolos

摘要:

我们发展了一个模型来描述通过幺正重子-介子耦合通道方法动态产生的奇宇称重子共振。该方案适用于轻和/或重夸克内容的通道。该模型的显著特点是:(1)相互作用是S波接触相互作用;(2)当包含轻赝标介子时,相互作用简化为SU(3)Weinberg-Tomozawa哈密顿量,从而尊重手征对称性;(3)自旋味在轻夸克扇区中保持不变;(4)重夸克自旋对称性在重夸克扇区中得到满足。特别地,在c或c-bar中具有不同含量的重子-介子态不混合。该模型是一个极小模型,不含自由参数。在这项工作中,我们专注于重子共振与隐藏的魅力(至少一个c-巴和一个c夸克)。我们分析了几个可能的扇区,对于净魅力为零的扇区,我们写出了与SU(3)和重夸克自旋对称性一致的最一般的拉格朗日量。我们研究了赝标介子和矢量介子与1/2+和3/2+重子在无粲和无奇异的隐粲区的S波相互作用产生的N态和Delta态。我们预测七个奇宇称N型和五个δ型状态,质量约为4 GeV,其中大部分是束缚态。这些态形成重夸克自旋多重态,它们的质量几乎是简并的。预测的新共振肯定不能容纳的夸克模型与三个组成夸克,他们可能会在未来的FAIR设施即将进行的熊猫实验中寻找。

英文摘要:

We develop a model to describe odd parity baryon resonances generated dynamically through a unitary baryon-meson coupled-channels approach. The scheme applies to channels with light and/or heavy quark content. Distinct features of the model are that, i) the interaction is an S-wave contact one, ii) it reduces to the SU(3) Weinberg-Tomozawa Hamiltonian when light pseudoscalar mesons are involved, thus, respecting chiral symmetry, iii) spin-flavor in preserved in the light quark sector, and iv) heavy quark spin symmetry is fulfilled in the heavy quark sector. In particular, baryon-meson states with different content in c or in c-bar do not mix. The model is a minimal one and it contains no free parameters. In this work, we focus on baryon resonances with hidden-charm (at least one c-bar and one c quarks). We analyze several possible sectors and, for the sector with zero net charm, we write down the most general Lagrangian consistent with SU(3) and heavy quark spin symmetry. We explicitly study the N and Delta states, which are produced from the S-wave interaction of pseudoscalar and vector mesons with 1/2+ and 3/2+ baryons within the charmless and strangeless hidden charm sector. We predict seven odd parity N-like and five Delta-like states with masses around 4 GeV, most of them as bound states. These states form heavy-quark spin multiplets, which are almost degenerate in mass. The predicted new resonances definitely cannot be accommodated by quark models with three constituent quarks and they might be looked for in the forthcoming PANDA experiment at the future FAIR facility.

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