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1. chinaXiv:201711.02319 [pdf]

Puzzle of the Λc spectrum

Qi-Fang Lu; Yubing Dong; Xiang Liu; Takayuki Matsuki
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

There is a puzzle in the +c family, i.e., one member with JP = 3/2+ is missing in a L = 2 multiplet which the heavy quark effective theory predicts, and JP’s of c(2765)+ and c(2940)+ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two c’s with unknown JP and the missing +c with 3/2+ for L = 2, and we find the most probable possibility that the peak corresponding to c(2880)+ actually includes a missing member with spin 3/2+ for L = 2 and that quantum numbers of c(2765)+ and c(2940)+ are 2S (1/2+) and 2P(1/2?), respectively.

submitted time 2017-11-10 Hits1015Downloads553 Comment 0

2. chinaXiv:201609.00006 [pdf]

Role of $Y(4630)$ in the $p\barp\rightarrow\Lambda_c\bar\Lambda_c$ reaction near threshold

Yan-Yan Wang; Qi-Fang Lu; En Wang; De-Min Li
Subjects: Physics >> Nuclear Physics

We investigate the charmed baryon production reaction?pp?→ΛcΛ?c?in an effective Lagrangian approach. Besides the?t-channel?D0?and?D?0?mesons exchanges, the?s-channel?Y(4630)?meson exchange is taken into account. For the total cross sections, the?D0?and?D?0?mesons provide minor background contributions, while the?Y(4630)?state gives a clear peak structure with the magnitude of 10?μb at center of mass energy 4.63 GeV. Basing on the results, we suggest that the reaction of?pp?→ΛcΛ?c?can be used to search for the?1???charmonium-like?Y(4630)?state, and our predictions can be tested in future by theP?ANDA?facility.

submitted time 2016-09-01 Hits751Downloads404 Comment 0

3. 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 Hits979Downloads506 Comment 0

4. 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 Hits964Downloads482 Comment 0

5. chinaXiv:201608.00210 [pdf]

Approximate degeneracy of heavy-light mesons with the same $L$

Takayuki Matsuki; Qi-Fang Lu; Yubing Dong; Toshiyuki Morii
Subjects: Physics >> Nuclear Physics

Careful observation of the experimental spectra of heavy-light mesons tells us that heavy-light mesons with the same angular momentum?L?are almost degenerate. The estimate is given how much this degeneracy is broken in our relativistic potential model, and it is analytically shown that expectation values of a commutator between the lowest order Hamiltonian and?L???2?are of the order of?1/mQ?with a heavy quark mass?mQ. It turns out that nonrelativistic approximation of heavy quark system has a rotational symmetry and hence degeneracy among states with the same?L. This feature can be tested by measuring higher orbitally and radially excited heavy-light meson spectra for?D/Ds/B/Bs?in LHCb and forthcoming BelleII.

submitted time 2016-08-31 Hits925Downloads445 Comment 0

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