Rapidity distribution of protons from the potential version of Ur QMD model and the traditional coalescence afterburner

Rapidity distributions of both E895 proton data at AGS energies and NA49 net proton data at SPS energies can be described reasonably well with a potential version of the Ur QMD in which mean-field potentials for both pre-formed hadrons and confined baryons are considered, with the help of a traditional coalescence afterburner in which one parameter set for both relative distance R_0 and relative momentum P_0,(3.8 fm, 0.3 Ge V/c), is used. Because of the large cancellation between the expansion in R_0 and the shrinkage in P_0 through the Lorentz transformation, the relativistic effect in clusters has little effect on the rapidity distribution of free(net) protons. Using a Woods-Saxon-like function instead of a pure logarithmic function as seen by FOPI collaboration at SIS energies, one can fit well both the data at SIS energies and the Ur QMD calculation results at AGS and SPS energies. Further, it is found that for central Au+Au or Pb+Pb collisions at top SIS, SPS and RHIC energies, the proton fractions in clusters are about33%, 10%, and 0.7%, respectively.

Net-Baryon and Net-Kaon Rapidity Distributions in Ultrarelativistic Heavy-Ion Collisions

In this paper,the gluon distribution is extracted from the KLR-AdS/CFT saturation model and used to investigate net-baryon and net-kaon rapidity distributions in ultrarelativistic heavy-ion collisions.With the same parameters of the saturation model fitting to HERA data and an χ 2 analysis of the overall constant C,the theoretical results are in good agreement with RHIC data in Au+Au collisions at √ s = 0.2 TeV.Then,we present the predictive results for net-baryon rapidity distributions in central Pb+Pb collisions at LHC energies of √ s = 2.76,3.94,and 5.52 TeV,and give the corresponding values of dN/dy for net-baryon at y = 0.

Modeling and Simulation for High Energy Sub-Nuclear Interactions Using Evolutionary Computation Technique

High energy sub-nuclear interactions are a good tool to dive deeply in the core of the particles to recognize their structures and the forces governed. The current article focuses on using one of the evolutionary computation techniques, the so-called genetic programming (GP), to model the hadron nucleus (h-A) interactions through discovering functions. In this article, GP is used to simulate the rapidity distribution of total charged, positive and negative pions for p--Ar and p--Xe interactions at 200 GeV/c and charged particles for p-pb collision at 5.02 TeV. We have done so many runs to select the best runs of the GP program and finally obtained the rapidity distribution as a function of the lab momentum , mass number (A) and the number of particles per unit solid angle (Y). In all cases studied, we compared our seven discovered functions produced by GP technique with the corresponding experimental data and the excellent matching was so clear.

The rapid climate change-caused dichotomy on subtropical evergreen broad-leaved forest in Yunnan： Reduction in habitat diversity and increase in species diversity

Yunnan's biodiversity is under considerable pressure and subtropical evergreen broad-leaved forests in this area have become increasingly fragmented through agriculture,logging,planting of economic plants,mining activities and changing environment.The aims of the study are to investigate climate changeinduced changes of subtropical evergreen broad-leaved forests in Yunnan and identify areas of current species richness centers for conservation preparation.Stacked species distribution models were created to generate ensemble forecasting of species distributions,alpha diversity and beta diversity for Yunnan's subtropical evergreen broad-leaved forests in both current and future climate scenarios.Under stacked species distribution models in rapid climate changes scenarios,changes of water-energy dynamics may possibly reduce beta diversity and increase alpha diversity.This point provides insight for future conservation of evergreen broad-leaved forest in Yunnan,highlighting the need to fully consider the problem of vegetation homogenization caused by transformation of water-energy dynamics.

Helium-3 production from Pb+Pb collisions at SPS energies with the UrQMD model and the traditional coalescence afterburner

A potential version of the UrQMD （UrQMD/M） transport model and a traditional coalescence model are combined to calculate the production of 3He fragments in central Pb＋Pb collisions at SPS energies 20-80 GeV/nucleon. It is found that the Lorentz transformation in the afterburner influences visibly the 3He yield and should be considered in calculations. The rapidity distribution of 3He multiplicities （including the concave shape） can be described well with UrQMD/M when it stops during tout=（100＋25） fm/c and the coalescence afterburner with one parameter set of （R0,P0）=（3.8 fm, 0.3 GeV/c） is taken into use afterwards.

Effects of inelastic (re)scattering processes s→gg and gg→s on strange hadron production in pp collisions at RHIC and LHC energies

The rapidity densities at mid-rapidity and the transverse momentum distributions for strange hadrons produced in pp collisions are analyzed using the modified PACIAE model by considering the effect of inelastic （re）scattering processes ss -→gg and gg→ss in parton （re）scattering. The calculated results of the transverse momentum spectra of the strangeness fitting with data measured by STAR and ALICE Collaborations can be improved, especially at large transverse momentum levels. This demonstrates that the effect of inelastic （re）scattering processes of ss→gg and gg→ss is not negligible at RHIC and LHC energy levels.