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1. chinaXiv:201711.02282 [pdf]

Decay width of d (2380) ! NN process in a chiral constituent quark model

Yubing Dong; Fei Huang; Pengnian Shen; Zongye Zhang
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

The width of three-body single-pion decay process d? → NNπ0,± is calculated by using the d? wave function obtained from our chiral SU(3) constituent quark model calculation. The e?ect of the dynamical structure on the width of d? is taken into account in both the single ?? channel and cou-pled ??+CC two-channel approximations. Our numerical result shows that in the coupled-channel approximation, namely, the hidden-color con?guration being considered, the obtained partial decay width of d? → NNπ is about several hundred KeV, while in the single ?? channel it is just about 2 ? 3 MeV. We, therefore, conclude that the partial width in the single-pion decay process of d? is much smaller than the widths in its double-pion decay processes. Our prediction may provide a criterion for judging di?erent interpretations of the d? structure, as di?erent pictures for the d? may result quite di?erent partial decay width.

submitted time 2017-11-10 Hits958Downloads528 Comment 0

2. chinaXiv:201609.01019 [pdf]

Neutral hidden charm pentaquark states $P_c^0(4380)$ and $P_c^0(4450)$ in $\pi^-p \to J/\psi n$ reaction

Qi-Fang L╱; Xiao-Yun Wang; Ju-Jun Xie; Xu-Rong Chen; Yu-Bing Dong
Subjects: Physics >> Nuclear Physics

We investigate the neutral hidden charm pentaquark states?P0c(4380)?and?P0c(4450)?in?π?p→J/ψnreaction within an effective Lagrangian approach. The background contributions for the process mainly come from?t-channel?π?and?ρ?meson exchanges. The contributions of?P0c(4380)?and?P0c(4450)?states give clear peak structures in the magnitude of 1?μb at center of mass energy 4.38 GeV and 4.45 GeV in the total cross sections. Hence, this reaction may provide a new good platform to search for neutral?Pc?states. It is expected that our estimated total cross sections together with the angular distributions can be tested by future experiments at J-PARC.

submitted time 2016-09-14 Hits665Downloads394 Comment 0

3. chinaXiv:201609.00950 [pdf]

Role of the $\Lambda^+_c(2940)$ in the $\pi^- p \to D^- D^0 p$ reaction close to threshold

Ju-Jun Xie; Yu-Bing Dong; Xu Cao
Subjects: Physics >> Nuclear Physics

We report on a theoretical study of the?π?p→D?D0p?reaction near threshold within an effective Lagrangian approach. The production process is described by?t?channel?D?0?meson exchange,?s-channel nucleon pole, and?u?channel?Σ++c?exchange. In our work, the final?D0p?results from the ground?Λ+c(2286)?state and also dominantly from the excited?Λ+c(2940)?state which is assumed as a?D?0p?molecular state with spin parity?JP=12+?or?12?. We calculate the total cross section of the?π?p→D?D0p?reaction. It is shown that the spin parity assignment of?12??for?Λ+c(2940)?gives a sizable enhancement for the total cross section in comparison with a choice of?Jp=12+. However, our theoretical result of the total cross section is sensitive to the value of the cutoff parameter involved in the form factor of the exchanged off-shell particles. Moreover, we also calculate the second order differential cross section and find it can be used to determine the parity of the?Λ+c(2940). It is expected that our model calculations can be tested by future experiments at J-PARC in Japan.

submitted time 2016-09-13 Hits664Downloads367 Comment 0

4. chinaXiv:201609.00887 [pdf]

A study of the $d^*(2380) \to d \pi \pi$ decay width

Yubing Dong; Pengnian Shen; Fei Huang; Zongye Zhang
Subjects: Physics >> Nuclear Physics

The decay widths of the?$\ds\to d \pi^0\pi^0$?and?$\ds\to d \pi^+\pi^-$?processes are explicitly calculated in terms of our chiral quark model. By using the experimental ratios of cross sections between various decay channels, the partial widths of the?$\ds\to pn \pi^0\pi^0$,?$\ds\to pn \pi^+\pi^-$,?$\ds\to pp \pi^0\pi^-$, and?$\ds\to nn \pi^+\pi^0$?channels are also extracted. Further including the estimated partial width for the?$\ds\to pn$?process, the total width of the?$\ds$resonance is obtained. In the first step of the practical calculation, the effect of the dynamical structure on the width of$\ds$?is studied in the single?ΔΔ?channel approximation. It is found that the width is reduced by few tens of MeV, in comparison with the one obtained by considering the effect of the kinematics only. This presents the importance of such effect from the dynamical structure. However, the obtained width with the single?ΔΔ?channel wave function is still too large to explain the data. It implies that the?$\ds$?resonance will not consist of the?ΔΔ?structure only, and instead there should be enough room for other structure such as the hidden-color (CC) component. Thus, in the second step, the width of?$\ds$?is further evaluated by using a wave function obtained in the coupled?ΔΔ?and CC channel calculation in the framework of the Resonating Group Method (RGM). It is shown that the resultant total width for?$\ds$?is about 69 MeV, which is compatible with the experimental observation of about 75 MeV and justifies our assertion that the?$\ds$?resonance is a hexaquark-dominated exotic state.

submitted time 2016-09-13 Hits710Downloads390 Comment 0

5. chinaXiv:201609.00004 [pdf]

Decay width of $d^*(2380)\to NN \pi\pi$ processes

Yubing Dong; Fei Huang; Pengnian Shen; Zongye Zhang
Subjects: Physics >> Nuclear Physics

The decay widths of four-body double-pion decays?$\ds\to pn \pi^0\pi^0$,?$\ds\to pn \pi^+\pi^-$, and iso-scalar parts of?$\ds\to pp \pi^0\pi^-$?and?$\ds\to nn \pi^+\pi^0$?are explicitly calculated with the help of the?d??wave function obtained in a chiral SU(3) quark model calculation. The effect of the dynamical structure on?$\ds$'s width is analyzed both in the single?ΔΔ?channel and coupled?ΔΔ?and?CC?channel approximations. It is found that in the coupled-channel approximation, the obtained partial decay widths of?$\ds\to pn \pi^0\pi^0$,?$\ds\to pn \pi^+\pi^-$, and those of?d??to the iso-scalar parts of?ppπ0π??and?nnπ+π0?are about?7.4MeV,?16.4MeV,?3.5MeV and?3.5MeV, respectively As a consequence, the total width is about?64.5MeV. These widths are consistent with those estimated by using the corresponding cross section data in our previous investigation and also the observed data. But in the single?ΔΔ?channel approximation, the widths are still almost 2-times larger than the measured values. Apparently, the explicitly calculated width together with the evaluated mass of?d??in the coupled?ΔΔ?and?CC?channel approximation can well explain the observed data, which again supports our assertion that the?$\ds$resonance is a six-quark dominated exotic state.

submitted time 2016-09-01 Hits800Downloads375 Comment 0

6. chinaXiv:201609.00003 [pdf]

Masses of open charm and bottom tetraquark states in relativized quark model

Qi-Fang Lu; Yu-Bing Dong
Subjects: Physics >> Nuclear Physics

We study the masses of open charm and bottom tetraquark states within the diquark-antidiquark scenario in the relativized quark model proposed by Godfrey and Isgur. The diquark and antidiquark masses are firstly solved by relativized quark potential, and then treated as the usual antiquark and quark, respectively. The masses of tetraquark states are obtained by solving the Schr\"{o}dinger-type equation between diquark and antidiquark. We find the masses of?sqb?q??tetraquark configuration are much higher than that of?X(5568). This conclusion disfavors the possibility of?X(5568)?as a tetraquark state within the diquark-antidiquark scenario. Further experimental searches are needed to clarify the nature of the signal observed by D0 collaboration.

submitted time 2016-09-01 Hits729Downloads364 Comment 0

7. chinaXiv:201608.00217 [pdf]

Strong decay mode $J/\psi p$ of hidden charm pentaquark states $P_c^+(4380)$ and $P_c^+(4450)$ in $\Sigma_c \barD^*$ molecular scenario

Qi-Fang Lu; Yu-Bing Dong
Subjects: Physics >> Nuclear Physics

We study the strong decay channels?P+c(4380)→J/ψp?and?P+c(4450)→J/ψp?under?ΣcD???molecular state ansatz. With various spin-parity assignments, the partial decay widths of?J/ψp?final state are calculated. Our results show that all the?P?wave?ΣcD???assignments are excluded, while?S?wave?ΣcD???pictures for?Pc(4380)?and?Pc(4450)?are both allowed by present experimental data. The?JP=3/2??Σ?cD??and?Σ?cD???molecules are also discussed in the heavy quark limit, and find that the?Σ?cD??system for?Pc(4380)?is possible. More experimental information on spin-parities and partial decay widths and theoretical investigations on other decay modes are needed to clarify the nature of the two?Pc?states.

submitted time 2016-08-31 Hits733Downloads363 Comment 0

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