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Typhoon rainstorms occur frequently in the southeastern coastal areas of China. The infiltration of rainwater under typhoon rainstorm conditions is an important cause of landslides in hilly mountains. Therefore, it is of great significance to study the migration law of rainwater infiltration wetting front under different geological environmental conditions. The temporal and spatial changes of rainfall infiltration were analyzed based on the monitoring data collected by the in-situ test of a landslide. A comprehensive rainfall infiltration model was established, which takes into account the nonuniform distribution of the initial water content of the soil and the slope environment. Then this model was verified by comparing to field test results and the predictions from existing classic models. The results demonstrate that: 1) At the initial stage of rainfall infiltration, the increasing slope of water content at different depths was steep. With the increase of time, the slope gradually slowed down. When the accumulated amount of rainfall reached 44.4 mm or more, the shape of the water profile changed from "Z" to reverse "S". As the rainfall intensity decreased, the type of rainwater infiltration process changed from water infiltration to non-water infiltration. At the later stage of infiltration, the growth rate of water content at different depths tended to be constant, and a stable infiltration stage was reached. 2) The migration speed of the wetting front increased with increasing rainfall. At the beginning of the rainfall, the rainwater infiltration rate was large. The migration speed of the wetting front was fast, and it decreased with the increase of soil depth. 3) The results of wetting front depth change over time calculated based on the improved rainfall infiltration model are consistent with the field monitoring test results, indicating that taking into account the slope angle and the inhomogeneity of the initial water content distribution can improve the accuracy of the predictions of the Green-Ampt model. The research results can have a certain significance for establishing an effective early warning model for landslides induced by the typhoon rainstorm.

Several methods for studying the nature of a resonance are applied to resonances recently discovered in the bottonomium and charmonium sectors. We employ the effective-range expansion, the saturation of the width and compositeness of a resonance, as well as direct fits to data. The latter stem from generic S -matrix parameterization that account for relevant dynamical features associated to channels that couple strongly in an energy region around the resonance masses, in which their thresholds also lie. We report on results obtained with these methods for the resonances Zb(10610), Zb(10650), Zcs(3985), Zc(3900), X(4020), X(6900), X(6825), and Pcs(4459).

The variation of the resonance poles, i.e., the mass and width, originating from changing the values of N C , the number of the QCD colors, provide an intuitive theoretical method to discriminate the interior constituents of hadrons. Many different approaches, including unitarized chiral amplitudes, dispersive methods, quark models, linear-sigma-model-like framework, etc., have been widely used to determine the N C trajectories of the various resonance pole positions. We focus on the discussions of the light-flavor meson resonances in this work. [ABSTRACT FROM AUTHOR]

In this work, we study the resonances near the thresholds of the open heavy-flavor hadrons using the effective-range-expansion method. The unitarity, analyticity, and compositeness coefficient are also taken into account in our theoretical formalism. We consider the Zc(3900), X(4020), χc1(4140), ψ(4260), and ψ(4660). The scattering lengths and effective ranges from the relevant elastic S-wave scattering amplitudes are determined. Tentative discussions on the inner structures of the aforementioned resonances are given. [ABSTRACT FROM AUTHOR]

We study the newly reported hidden-charm pentaquark candidates P c (4312) , P c (4440) and P c (4457) from the LHCb Collaboration, in the framework of the effective-range expansion and resonance compositeness relations. The scattering lengths and effective ranges from the S -wave Σ c D ¯ and Σ c D ¯ ⁎ scattering are calculated by using the experimental results of the masses and widths of the P c (4312) , P c (4440) and P c (4457). Then we calculate the couplings between the J / ψ p , Σ c D ¯ channels and the pentaquark candidate P c (4312) , with which we further estimate the probabilities of finding the J / ψ p and Σ c D ¯ components inside P c (4312). The partial decay widths and compositeness coefficients are calculated for the P c (4440) and P c (4457) states by including the J / ψ p and Σ c D ¯ ⁎ channels. Similar studies are also carried out for the three P c states by including the Λ c D ¯ ⁎ and Σ c D ¯ (⁎) channels. [ABSTRACT FROM AUTHOR]

Abstract: The meson–baryon scattering with strangeness −1 is studied within the coupled-channel unitary chiral perturbation theory. A large amount of experimental data are analyzed. This strongly constrains the free parameters in our calculation and also the resulting meson–baryon scattering amplitudes. Several different strategies to perform the fits to data are discussed, which allows one to make the important check on the stability of the results obtained. Our final threshold parameters for scattering and baryon resonance properties are stable and confident. [Copyright &y& Elsevier]

Abstract: We perform a complete one-loop calculation of meson–meson scattering, and of the scalar and pseudoscalar form factors in chiral perturbation theory with the inclusion of explicit resonance fields. This effective field theory takes into account the low-energy effects of the QCD anomaly explicitly in the dynamics. The calculations are supplied by non-perturbative unitarization techniques that provide the final results for the meson–meson scattering partial waves and the scalar form factors considered. We present thorough analyses on the scattering data, resonance spectroscopy, spectral functions, Weinberg-like sum rules and semi-local duality. The last two requirements establish relations between the scalar spectrum with the pseudoscalar and vector ones, respectively. The extrapolation of the various quantities is studied as well. The fulfillment of all these non-trivial aspects of the QCD dynamics by our results gives a strong support to the emerging picture for the scalar dynamics and its related spectrum. [Copyright &y& Elsevier]

We study the scattering of the light-flavor pseudoscalar mesons (π,K,η) off the ground-state charmed mesons (D,Ds) within chiral effective field theory. The recent lattice simulation results on various scattering lengths and the finite-volume spectra both in the moving and center-of-mass frames, most of which are obtained at unphysical meson masses, are used to constrain the free parameters in our theory. Explicit formulas to include the S- and P-wave mixing to determine the finite-volume energy levels are provided. After a successful reproduction of the lattice data, we perform a chiral extrapolation to predict the quantities with physical meson masses, including phase shifts, inelasticities, resonance pole positions and the corresponding residues from the scattering of the light pseudoscalar and charmed mesons. [ABSTRACT FROM AUTHOR]