Dibaryons without Strangeness

摘要: 在手征SU（3） 夸克模型下应用共振群方法讨论了三个非奇异的双重子态的性质。计算中的模型参数取自我们以前的工作，拟合核子核子相互作用散射相移确定下来的。首先，研究了氘核的性质，这是非常重要的，因为氘核是多年来实验上唯一发现的双重子态。氘核属于核子核子系统，它是自旋为S =1 和同位旋为T =0 的双重子态。我们计算了氘核的结合能、散射长度以及氘核的相对运动波函数，结果表明手征SU（3） 夸克模型可以合理描述氘核的性质并且发现张量力对形成松散束缚态的氘核是重要的。然后，给出了S = 3 和T =0 的ΔΔ双重子态的理论预言结果，这里考虑了分波耦合和隐色道耦合效应，计算了结合能和均方根半径。结果表明，隐色道耦合效应比分波耦合效应大，也就是说隐色道耦合效应在形成（ΔΔ）_{ST=30} 双重子态中是重要的。我们的理论预言结果在几十个MeV 左右，低于ΔΔ道的阈值但是高于NΔπ的阈值. 出乎意料地，我们的预言结果很接近最近2014 年WASA的实验结果。接着，给出了对S = 0 和T =3 的ΔΔ双重子态性质的最新研究结果，这里在以前的单道计算基础上考虑了隐色道耦合效应。结果表明，隐色道耦合对（ΔΔ）ST=03的结合能也有较大的影响。但是，和（ΔΔ）_{ST=30} 一样，它的质量低于ΔΔ道的阈值但是高于NΔπ的阈值。最后，对S = 3 以及S = 0 两个不同ΔΔ自旋态，详细比较了两者结构之间的差异。结果表明，σ'介子交换和OGE 交换对自旋S = 0 和S = 1 态提供的吸引作用分别是主要的，从而导致耦合道计算中系统的结合能变大。
In the present work we discuss three dibaryons without strangeness in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. In the calculation, the model parameters are taken from our previous work in which the nucleonnucleon (NN) scattering phase shifts are fitted quite well. Firstly, the structure of deuteron is discussed, which is very important since it is the first dibaryon confirmed by experiment in the past many years. Deuteron belongs to NN system with spin S =1 and isospin T =0, the binding energy, scattering length and the relative wave functions of deuteron are discussed. The results show that the chiral SU(3) quark model describes the properties of deuteron quite well and tensor interaction is important in forming the deuteron loosely bound. Secondly, the predicted results of ΔΔ dibaryon with S =3 and T =0 are shown, the resultant binding energy and size of rootmeansquare (RMS) of six quarks are calculated by including the L coupling and hidden color channel (CC) coupling. The results show that the CC coupling effect is much larger than the L mixing effect, which means that CC coupling plays an important role in forming the spin S =3 ΔΔ dibayon state. Our predicted binding energy is several tens MeV, it is lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ. Unexpectedly, our predicted mass is quite close to the recent confirmation by WASA experiments in 2014. Thirdly, we present our new results of ΔΔ dibaryon with S = 0 and T =3, obtained recently by extending the singlechannel calculation to including the CC coupling. It is seen that the CC coupling also has a relatively large effect on (ΔΔ)ST=03 state. However, its mass is still lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ, similar as that of (ΔΔ)_{ST=30} state. Finally, we further make some comparisons between S = 3 and S = 0 ΔΔ states to show the difference of the two dibaryons. The results show that the attractive interactions from σ' meson and OGE exchanges are dominantly important for S =0 and S =3 states, respectively, so their binding energies all become larger in coupledchannel calculation.Abstract: In the present work we discuss three dibaryons without strangeness in the chiral SU(3) quark model by solving the resonating group method (RGM) equation. In the calculation, the model parameters are taken from our previous work in which the nucleonnucleon (NN) scattering phase shifts are fitted quite well. Firstly, the structure of deuteron is discussed, which is very important since it is the first dibaryon confirmed by experiment in the past many years. Deuteron belongs to NN system with spin S =1 and isospin T =0, the binding energy, scattering length and the relative wave functions of deuteron are discussed. The results show that the chiral SU(3) quark model describes the properties of deuteron quite well and tensor interaction is important in forming the deuteron loosely bound. Secondly, the predicted results of ΔΔ dibaryon with S =3 and T =0 are shown, the resultant binding energy and size of rootmeansquare (RMS) of six quarks are calculated by including the L coupling and hidden color channel (CC) coupling. The results show that the CC coupling effect is much larger than the L mixing effect, which means that CC coupling plays an important role in forming the spin S =3 ΔΔ dibayon state. Our predicted binding energy is several tens MeV, it is lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ. Unexpectedly, our predicted mass is quite close to the recent confirmation by WASA experiments in 2014. Thirdly, we present our new results of ΔΔ dibaryon with S = 0 and T =3, obtained recently by extending the singlechannel calculation to including the CC coupling. It is seen that the CC coupling also has a relatively large effect on (ΔΔ)ST=03 state. However, its mass is still lower than the threshold of the ΔΔ channel and higher than the mass of NΔπ, similar as that of (ΔΔ)_{ST=30} state. Finally, we further make some comparisons between S = 3 and S = 0 ΔΔ states to show the difference of the two dibaryons. The results show that the attractive interactions from σ' meson and OGE exchanges are dominantly important for S =0 and S =3 states, respectively, so their binding energies all become larger in coupledchannel calculation.
Key words:
 deuteron /
 tensor force /
 dibaryon /
 hidden color channel

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