Partial wave scattering cross sections for He-HBr collision

A new anisotropic potential is fitted to ab initio data. The close-coupling approach is utilized to calculate state-tostate rotational excitation partial wave cross sections for elastic and inelastic collisions of He atom with HBr molecule based on the fitted potential. The calculation is performed separately at the incident energies： 75, 100 and 200 meV.The tendency of the elastic and inelastic rotational excitation partial wave cross sections varying with total angular quantum number J is obtained.

The effect of the attractive well of the potential energy surface for Ne-HC1 on rotationally inelastic partial wave cross sections

An interaction potential of the Ne-HC1 van der Waals complex is obtained by utilizing the Huxley analytic potential function to fit the accurate interaction energy data, which have been computed at the coupled cluster singles and doubles including connected triple excitations level and with the augmented correlation consistent polarized valence quintuple zeta basis set extended with a set of 3s3p2dlflg mid-bond functions [CCSD （T）/aug-cc-pV5Z-33211]. The close coupling calculation of state-to-state partial cross sections for collision of Ne with HC1 is first performed by employing the fitted interaction potential. This calculation is performed at the incident energies： 40, 60, 75 and 100 meV, separately. The effects of the long-range attractive and the short-range anisotropic interactions on the inelastic state-to-state partial cross sections are discussed in detail. Two maxima are present in the rotationally inelastic partial cross sections and they originate from different mechanisms.

Research on Partial Coefficients for Design of Quarter-circular Caisson Breakwater

The quarter-circular caisson breakwater （QCB） is a new type of breakwater, and it can be applied in deepwater. The stability of QCB under wave force action can be enhanced, and the rubble mound engineering can be less than that of semi-circular breakwaters in deepwater. In order to study the wave force distribution acting on the QCB, to find wave force formula for this type of breakwater, firstly in this paper, the distribution characteristics of the horizontal force, the downward vertical force and the uplift force on the breakwater were gotten based on physical model wave flume experiments and on the analysis of the wave pressure experimental data. Based on a series of physical model tests acted by irregular waves, a kind of calculation method, which was modified by Goda formula, was proposed to carry out the wave force on the QCB. Secondly, the reliability method with correlated variables was adopted to analyze the QCB, considering the high correlation between wave forces or moments. Utilizing the observed wave data in engineering field, the reliability index and failure probability of QCB were obtained. Finally, a factor Q=0.9 is given to modify the zero pressure height above SWL of QCB, and wave force partial coefficient 1.34 to the design expressions of QCB for anti-sliding, as well as 1.67 for anti-overturning, were presented.

High sensitive detection of high-order partial wave scattering in photoassociation of ultralcold atoms

We report on the observation of enhanced high-order partial wave scattering from atom atom interaction via changing the temperature of a magneto optical trap in the process of photoassociation. The high-order scattering partial wave is directly manifested through the large signal amplitude of the rovibrational resonance levels of trap-loss spectroscopy from photoassociation.

Differential cross sections of elastic electron scattering from CH4. CF4 and SF6 in the energy range l00-700eV

We investigate the differential cross sections （DCS） of elastic electron scattering from CH4, CF4 and SF6 at six impact energies in a range of 100 700eV by employing the independent atom model （IAM） together with the relativistic partial waves. The atom is present in an optical potential which is complex, spherically symmetric, and energy dependent. The optical potential of the atom is the sum of the direct static, dynamic polarization, local exchange and modified absorption potentials. The results obtained by using a modified absorption potential show significant improvements on the unmodified absorption potential results. The present results are generally in good agreement with experimental data available. In addition, the present results indicate that the structure of molecule manifests the observable effects on electron- molecule scattering.

Three-dimensional numerical simulation of wave interaction with perforated quasi-ellipse caisson

The finite difference method and the volume of fluid （VOF） method were used to develop a three-dimensional numerical model to study wave interaction with a perforated caisson. The partial cell method was adopted to solve this type of problem for the first time. The validity of the present model, with and without the presence of caisson structures, was examined by comparing the model results with experimental data. Then, the numerical model was used to investigate the effects of various wave and structure parameters on the wave force and wave runup of the perforated quasi-ellipse caisson. Compared with the solid quasi-ellipse caisson, the wave force on the perforated quasi-ellipse caisson is significantly reduced with increasing porosity of the perforated quasi-ellipse caisson. Furthermore, the perforated quasi-ellipse caisson can also reduce the wave runup, and it tends to decrease with the increase of the porosity of the perforated quasi-ellipse caisson and the relative wave height.

Electron impact excitation of helium atom

A method to deal with the electron impact excitation cross sections of an atom from low to high incident energies are presented. This method combines the partial wave method and the first Born approximation(FBA), i.e., replacing the several lowest partial wave cross sections of the total cross sections within FBA by the corresponding exact partial wave cross sections. A new set of codes are developed to calculate the FBA partial wave cross sections. Using this method,the convergent e–He collision cross sections of optical-forbidden and optical-allowed transitions at low to high incident energies are obtained. The calculation results demonstrate the validity and efficiency of the method.

An effective method to calculate the electron impact excitation cross sections of helium from ground state to a final channel in the whole energy region

The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of helium as an illustration example. The optical forbidden 1^(1)S–n^(1)S(n = 2–4) and optical allowed 1^(1)S–n^(1)P(n = 2–4) excitation cross sections are calculated in the whole energy region using the scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections,which should be very useful in the related application fields. The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00142.

Wave Reflection Caused by Wave Overtopping and Sloping Top of Spructure

In this paper, the theoretical analysis and experimental studies are employed to investigate the reflection characteristics of partial standing waves caused by wave overtopping and sloping top of structures. Based on the principle of conservation of wave energy flux, the third-order Stokes wave theory is used to formulate the reflection coefficient at wave overtopping; the calculation results are regressed into an applied expression. A series of experiments of wave reflection for a vertical-wall structure with chamfered and overhanging upper sections are carried out to investigate the influence of top slope on wave reflection. The regularity of variation of wave reflection in this case is analysed based on the experimental results.

Partial wave analysis of ψ' →γχ_(c0) →γpK-Λ used for searching for baryon resonance

Abundant ψ＇ events have been collected at the Beijing Electron Positron Collider-Ⅱ （BEPCⅡ） that could undoubtedly provide us with a great opportunity to study the more attractive charmonium decays. As has been noticed before, in the process of J/ψ＇ decaying to the baryonic final states, pK-Λ, the evident Λ＊ and N＊ bands have been observed. Similarly, by using the product of χcJ from ψ＇ radiative decay, we may confirm this or find some extra new resonances. χc0＇s data samples will be more than χc1,2, taking into account the larger branching ratio of ψ＇ →γχc0. Here, we provide explicit partial wave analysis formulae for the very interesting channel ψ＇ →γχc0 →γpK-Λ.

Lepton mass correction in partial wave analyses of charmed meson semi-leptonic decays

We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting newψ(3770)→DD data,our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.

Single-particle spectroscopies of p-wave and d-wave interacting Bose gases in normal phase

Motivated by experiments with interacting quantum gases across high partial wave resonance,we investigate the thermodynamic properties and single-particle spectra of Bose gases in normal phase for different interaction strengths for both p-and d-wave interactions.The equation of state,contact density,momentum distributions and self-energies of single-particle Green’s functions are obtained in the spirit of ladder diagram approximations.The radio-frequency(RF)spectrum,as an important experimental approach for detecting Feshbach molecules or the interaction effect,is calculated at different temperatures.A reversed temperature dependence on the Bose–Einstein condensation side and Bardeen–Cooper–Schrieffer side is identified for both p-and d-wave interactions.An estimate for the signal of RF spectra under typical experimental conditions is also provided.

Non-Relativistic Phase Shifts for Scattering on Generalized Radial Yukawa Potentials

Non-relativistic phase shifts for a generalized Yukawa potential V(r) =-V_0( e^(-αr)/r)-V_1( e^(-2αr)/r^2) are studied by the amplitude-phase method and by a frequently used analytic method based on a Pekeris-type approximation of power-law potential terms.Small variations of V_1 seem to have marginal effects on the effective potential and on exact phase shifts.However,as pointed out in this study,a Pekeris-type approximation in scattering applications often implies serious distortions of both effective potentials and phase shifts.The Pekeris-type based analytic approximation in this study seems to give low-quality scattering results for this model potential at low energies.

Recent results on light hadron spectroscopy from BESⅡ

We reported the observation of Y（2175） in Фfo（980） mass spectrum in J/ψ → ηФfo（980） with fo（980） →π＋π^- and the observation of a broad 1^-- resonance of K^＋K^- mass in J/ψ→ K^＋K^-π^0. The results from the partial wave analyses of J/ψ→γπ^＋π^- and γπ^0π^0, as well as J/ψ →pK^-∧. are also presented.

Search for exotic state 1^(-+) π_1(1400) at BESⅢ

The J/ψ hadronic decays provide good laboratory to search for the hybrid states with exotic quantum numbers. A full Partial Wave Analysis （PWA） is performed to the generated Monte Carlo J/ψ→ ρηπ data, based on the design of BESⅢ detector, to study the sensitivity of searching for a possible exotic state at BESⅢ.

Singularities and accumulation of singularities ofπN scattering amplitudes

It is demonstrated that for the isospin I=1/2πN scattering amplitude,T^(I=1/2)(s,t),s=(m_(N)^(2)-m_(π)^(2))^(2)/m_(N)^(2)and s=m_(N)^(2)+2m_(π)^(2)are two accumulation points of poles on the second sheet of complex s plane,and are hence accumulation of singularities of T^(I=1/2)(s,t).For T^(I=3/2)(s,t),s=(m_(N)^(2)-m_(π)^(2))^(2)/m_(N)^(2)is the accumulation point of poles on the second sheet of the complex s plane.The proof is valid up to all orders of chiral expansions.

Centrifugal–Barrier Efects and Determination of Interaction Radius

The interaction radius of a resonance is an important physical quantity to describe the structure of a resonance. But, for a long time, physicists do not find a reliable way to measure the magnitude of the interaction radius of a resonance. In this paper, a method is proposed to measure the interaction radius in physics analysis. It is found that the centrifugal barrier effects have great influence to physical results obtained in the PWA fit, and the interaction radius of some resonances can be well measured in the fit.

Nucleon resonances in πN→η'N and J/ψ→pη'

We are aiming to study the J/ψ →pqη′ decay in an isobar model and the effective Lagrangian approach on the basis of the coupling constants extracted from the πN→η′ reaction. After a careful exploration of the contributions of the S11（1535）, P11（1710）, P13（1900）, S11（2090） and Pl,（2100） resonances, we conclude that either a subthreshold resonance or a broad P-wave state in the near threshold range seems to be indispensable to describe the present data of the πN→η′.Furthermore, at least one broad resonance above rl＇N threshold is preferred. With this detailed analysis, we give the invariant mass spectrum and Dalitz plot of the J/ψ →pqη′decay for the purpose of assisting the future detailed partial wave analysis. It is found that the J/ψ →pqη′ data are useful for disentangling the above or below threshold resonant contribution, though it still further needs the differential cross section data of πN→η′ to realize some of the resonant and non-resonant contribution.

Disentangling the nature of resonances in coupled-channel models

We present severM possible hadronic states found in coupled-channel models within the on-shell approx- imation. The interaction potential is constructed as a sum of the tree-level Feynman diagrams calculated with the effective Lagrangians. Based on the recent empirical data, we illustrate the possible existence of severM baryonic and mesonic states with definite quantum numbers in the model. We give their properties for the purpose of further study and discuss the potential of finding them in future experiments.

An N/D study of the S_(11)channelπN scattering amplitude

Extensive dynamical N/D calculations are conducted in the study of S_(11) channel low energy πN scatterings,based on various phenomenological model inputs of left cuts at the tree level.The subtleties of the singular behavior of the partial wave amplitude,at the origin of the complex s plane,are analysed in detail.Furthermore,it is found that the dispersion representation for the phase shift,δ,must be modified in the case of πN scatterings.An additional contribution from the dispersion integral exists,which approximately cancels the contribution of the two virtual poles located near the end points of the segment cut,induced by u channel nucleon exchanges.With limited reliance on the details of the dynamical inputs,the subthreshold resonance N*(890)survives.