Compared with the charmed baryons, the bottom baryons are not very well known, either experimentally Or theoretically. In this paper, we investigate the dipion strong decays of the P-wave and D-wave excited bottom baryons in the framework of the QPC model. We also extend the same analysis to the charmed baryons.
A chiral quark model is applied to calculate the spectra of pseudoscalar mesons η and η . By analyzing the obtained spectra, we find that the mesons η （2 1 S 0 ）, η（4 1 S 0 ）, η （3 1 S 0 ） and η （4 1 S 0 ） are the possible candidates of η（1760）, X（1835）, X（2120） and X（2370）. The strong decay widths of these pseudoscalars to all the possible two-body decay channels are calculated within the framework of the 3 P 0 model. Although the total width of η （21S0 ） is compatible with the BES Collaboration＇s experimental value for η（1760）, the partial decay width to ωω is too small, which is not consistent with the BES result. If X（1835） is interpreted as η（4 1 S 0 ）, the total decay width is compatible with the experimental data, and the main decay modes will be πa 0 （980） and πa 0 （1450）, which needs to be checked experimentally. The assignment of X（2120） and X（2370） to η （31S0 ） and η （41S0 ） is disfavored in the present calculation because of the incompatibility of the decay widths.
The electromagnetic form factors of the deuteron, particularly its quadrupole form factor, are studied with the help of a phenomenological Lagrangian approach where the vertex of the deuteron proton-neutron with D-state contribution is explicitly taken into account. The results show the importance of this contribution to the deuteron quadrupole form factor in the approach.
One of the puzzling questions in modern high energy physics is whether monopoles exist in realistic theories of fundamental interactions. The well-known singular monopoless[1,2] cannot represent physical observable objects. In this regard, composite monopole solutions described within the framework of the standard electroweak model could be more favorable candidates for monopoles expected to be found at LHC. So far, known solutions either lack a regular structure or need essential extension beyond the standard model.
We report on a theoretical study of the hidden charm N＊cc states in the γp→ D＊0∧＋c reaction near threshold within an effective Lagrangian approach. In addition to the contributions from the s-channel nucleon pole, the t-channel Do exchange, the u-channel A＋ exchange and the contact term, we study the contributions from the N＊cc states with spin-parity JP=1/2- and 3/2-. The total and differential cross sections of the γp→ D＊0∧＋c reaction are predicted. It is found that the contributions of these N＊cc states give clear peak structures in the total cross sections. Thus, this reaction is another new platform to study the hidden-charm states. It is expected that our model calculation may be tested by future experiments.
Using the one-boson-exchange model,we studied the possible existence of very loosely bound hidden-charm molecular baryons composed of an anti-charmed meson and a charmed baryon.Our numerical results indicate that the Σ c ＊ and Σ c states exist,but that the Λ c and Λ c ＊ molecular states do not.
In the past decade,more and more charmoniumlike and bottomoniumlike states have been reported in experiments,which have led us to extensive discussions on the underlying structure of these states.In this review,we briefly summarize the experimental and theoretical status of these observed states.
