Final-state Rescatterings of Kaons in Relatiyistic Nuclear Collisions

In recent years the studies of the relativistic heavy-ion collisions give rise to extensive interest. One of the motivations of these studies is to probe the equation of state (EOS) of nuclear matter at high density and/or temperature. This is very significant for nuclear physics and particle physics and astrophysics. The kaons produced in the process of nuclear collisions at an incident energy of about

Calibration of quantitative rescattering model for simulating vortex high-order harmonic generation driven by Laguerre–Gaussian beam with nonzero orbital angular momentum

We calibrate the macroscopic vortex high-order harmonic generation(HHG)obtained by the quantitative rescattering(QRS)model to compute single-atom induced dipoles against that by solving the time-dependent Schr?dinger equation(TDSE).We show that the QRS perfectly agrees with the TDSE under the favorable phase-matching condition,and the QRS can accurately predict the main features in the spatial profiles of vortex HHG if the phase-matching condition is not good.We uncover that harmonic emissions from short and long trajectories are adjusted by the phase-matching condition through the time-frequency analysis and the QRS can simulate the vortex HHG accurately only when the interference between two trajectories is absent.This work confirms that it is an efficient way to employ the QRS model in the single-atom response for precisely simulating the macroscopic vortex HHG.

Effect of multiple rescattering processes on harmonic emission in spatially inhomogeneous field

The effect of multiple rescattering processes on the harmonic emission from He atom in a spatially inhomogeneous field is discussed by solving the one-dimensional time-dependent Schrtdinger equation and the classical equation of motion. By establishing the physical model of the harmonic emission in the inhomogeneous field, we discuss the related characters of the multiple rescatterings process in the harmonic generation process. It shows that the second rescattering rather than the first rescattering tends to determine the harmonic cutoff energy when the inhomogeneous parameter is larger than 0.0055. Additionally, with the classica/simulation, the underlying physical mechanism of the continuum-continuum harmonics is also revealed. Moreover, this work may provide new physical insight into the harmonic generation in an inhomogeneous field, and is beneficial to further extract the harnaonic emission from molecular systems.

Study on Non-Sequential Double Ionization of Aligned Diatomic Molecules in Strong Laser Fields

We develop a semiclassical model to describe the non-sequential double ionization of aligned diatomic molecules in an intense linearly polarized field. It is found that in the tunnelling regime, the oriented molecule shows geometric effects on double ionization process when aligned parallel and perpendicular to the external field. Our results are qualitatively consistent with the recent experimental observations.

Nonadiabatic Effect on the Rescattering Trajectories of Electrons in Strong Laser Field Ionization Process

The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero （positive or negative） initial momentum is applied.

Calculation of the photoelectron spectra under a scaling transform

By solving the time-dependent Schr6dinger equation, the dependence of photoelectron energy spectra on the binding energy of targets, wavelength and the intensity of laser pulse is exhibited and a scaling law of kinetic energy spectra of both the direct and the rescattered photoelectrons is concluded. The scaling law provides a convenient tool to determine the equivalent photoionization process of various atoms or molecules in various laser fields. The verification of the scaling law by independent methods provides incontestable support to the validity of the scaling law.

Quantitative rescattering theory for nonsequential double ionization

We review the recently improved quantitative rescattering theory for nonsequential double ionization, in which the lowering of threshold due to the presence of electric field at the time of recollision has been taken into account. First,we present the basic theoretical tools which are used in the numerical simulations, especially the quantum theories for elastic scattering of electron as well as the processes of electron impact excitation and electron impact ionization. Then,after a brief discussion about the properties of the returning electron wave packet, we provide the numerical procedures for the simulations of the total double ionization yield, the double-to-single ionization ratio, and the correlated two-electron momentum distribution.

Multiple-plateau structure and scaling relation in photoelectron spectra of high-order above-threshold ionization

By developing a full quantum scattering theory of high-order above-threshold ionization,we study the energy spectra and the angular distributions of photoelectrons from atoms with intense laser fields shining on them.We find that real rescattering can occur many times,and even infinite times.The photoelectrons from the rescattering process form a broad plateau in the kinetic-energy spectrum.We further disclose a multiple-plateau structure formed by the high-energy photoelectrons,which absorb many photons during the rescattering process.Moreover,we find that both the angular distributions and the kinetic-energy spectra of photoelectrons obey the same scaling law as that for directly emitted photoelectrons.

Parton Rescattering Effect on the Charged Hadron Forward-Backward Multiplicity Correlation in pp Collisions at s～(1/2)=200 GeV

The parton rescattering effect on the charged hadron forward-backward multiplicity correlation in pp collisions at √s =200 GeV is studied by a parton and hadron cascade model, PACIAE, based on the PYTHIA model. The calculated multiplicity and pseudorapidity distribution of the final state charged hadrons are well compared with the experimental data. It is found that the final state charged hadron pseudorapidity distribution is different from the initial state charged partons. The parton rescattering effect on the charged hadron forward-backward multiplicity correlation increases with the increasing parton rescattering strength in the center pseudorapidity region （｜η｜ 〈 1）. However, this effect becomes weaker in the outer pseudorapidity region （｜η｜ 〉 1）.

Evidence of potential change in nonsequential double ionization

Recently,the quantitative rescattering model(QRS)for nonsequential double ionization(NSDI)is modified by taking into account the potential change(PC)due to the presence of electric field at the time of recollision.Using the improved QRS model,we simulate the longitudinal momentum distributions of doubly charged ions He2+by projecting the correlated two-electron momentum distributions for NSDI of He onto the main diagonal.The obtained results are compared directly with the experimental data at different intensities.It is found that when the PC is considered,the width of momentum distributions reduces and the agreement between theory and experiment is improved.

Towards the decays of X(1625) in the molecular picture

In this talk, we firstly overview the experimental status of Nx（1625）, which is an enhancement structure observed in K-3. invariant mass spectrum of J/ψ → pK-∧. process. Then we present the result of the decay of Nx（1625） under the two molecular assumptions, i.e. S-wave∧K- and S-wave ∑0K- molecular states. Several experimental suggestions for Nx （1625） are proposed.

Scattering-amplitude phase in spiderlike photoelectron momentum distributions

The spiderlike structures in the photoelectron momentum distributions of ionized electrons from the hydrogen atom are numerically simulated by using a semiclassical rescattering model(SRM) and solving the time-dependent Schrodinger equation(TDSE),focusing on the role of the phase of the scattering amplitude.With the SRM,we find that the spiderlike legs shift to positions with smaller transverse momentum values while increasing the phase.The spiderlike patterns obtained by SRM and TDSE are in good agreement upon considering this phase.In addition,the time differences in electron ionization and rescattering calculated by SRM and the saddle-point equations are either in agreement or show very similar laws of variation,which further corroborates the significance of the phase of the scattering amplitude.

Vector meson rescattering effect in understanding the threshold enhancement observed in J/ψ→γp

We propose one possible mechanism,i.e.,the vector meson （VV） rescattering effects,to interpret the near threshold narrow enhancement observed in J/ψ → γpp.The estimate indicates that these effects can give sizeable contributions to this channel,and a destructive interference between different rescattering amplitudes is required to reproduce the line shape of the data.

Rescattering mechanism of weak decays of double-charm baryons

The doubly charmed baryon■cc++was recently observed by LHCb via the decay processes of■cc++→∧+cK^(-)π^(+)π^(+)and■c+π^(+).These discovery channels were successfully predicted in a framework in which the short-distance contributions are calculated under the factorization hypothesis and the long-distance contributions are estimated using the rescattering mechanism for the final-state-interaction effcts.In this paper,we illustrate the above framework in detail by systematic studies on the tw o-body baryonic decays Bcc→BcP involving the doubly charmed baryons Bcc=(■cc++,■cc++,Ωcc+),the singly charmed baryons Bc=(B3,B6)and the light pseudoscalar mesons P=(π,K,η1,8).