分类： 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间： 2017-11-10
摘要： 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.
分类： 物理学 >> 核物理学 提交时间： 2016-09-01
摘要： 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.
分类： 物理学 >> 核物理学 提交时间： 2016-09-01
摘要： 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.
分类： 物理学 >> 核物理学 提交时间： 2016-08-31
摘要： 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.
分类： 物理学 >> 核物理学 提交时间： 2016-08-31
摘要： 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 L⃗ 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.
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