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ZHENG Yu-Ming FUCHS C. SRISAWAS Pornrad FAESSLER Amand YAN Yu-Peng KOBDAJ Chinorat XING Yong-Zhong 《理论物理通讯》2008,50(9):725-728
The sigma meson production in p + ^12C and p A- ^40Ca reactions at the incident energy Ep = 1.5 GeV is investigated within the Quantum Molecular Dynamics model. The simulation results indicate a distinctive A dependence of the sigma production, that is, the increase of A is followed by an increase of the production cross sections. We find that the σ meson production in proton-induced reactions is strongly medium-dependent, and the produced σ mesons decaying in a denser medium experience a stronger mass shift towards lower masses. This mass shift is an experimentally accessible observable in the final state pion pairs, which do not suffer from reabsorption by the surrounding nucleons. It is pointed out that the ratio of measured sigma cross sections as a function of the sigma invariant-mass from various reactions is a good probe to explore the existence of the σ meson in a dense nuclear environment. 相似文献
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The collective flow of positive charged kaons in heavy ion reactions at SIS energy is investigated within the frame of covariant kann dynamics. The theoretical results calculated by using quantum molecular dynamics show that the rapidity distribution of K^+ mesons is more sensitive to the nuclear equation of state than the differential directed flow. The contribution of various K^+ production reaction channels to the rapidity distribution of the K^+ is also analysed in detail. The results indicate that the rapidity distribution of K^+ mesons is mainly from the contribution of the N-△ and N-N channel. This means that the delta resonance state plays a predominantly important role for the K^+ subthreshold production. 相似文献
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ZHENG Yu-Ming FUCHS Christian FAESSLER
Amand SHEKHTER
Kirril SRISAWAD Pornrad KOBDAJ
Chinorat YAN Yu-Peng 《理论物理通讯》2004,41(5):746-750
The influence of the chiral mean field on the K+ in-plane
flow in heavy ion collisions at SIS energy is investigated within covariant kaon dynamics. For the kaon mesons inside the nuclear medium a quasi-particle picture including
scalar and vector fields is adopted and compared to the standard treatment with a static potential. It is confirmed that a Lorentz force from spatial component of the vector field provides
an important contribution to the in-medium kaon dynamics and
strongly counterbalances the influence of the vector potential
on the K+ in-plane flow. The calculated results show that
the new FOPI data can be reasonably described using the
Brown & Rho parametrization, which partly takes into account
the correction of higher order contributions in the chiral
expansion. This indicates that one can abstract the information
on the kaon potential in a nuclear medium from the analysis of
the K+ in-plane flow. 相似文献
4.
Wanchaloem Poonsawat Ayut Limphirat Dai-Mei Zhou Yu-Liang Yan Pornrad Srisawad Chinorat Kobdaj Yupeng Yan Ben-Hao Sa 《Few-Body Systems》2014,55(8-10):1041-1043
The parton and hadron cascade model, PACIAE 2.0, is employed to calculate the net-proton nonstatistical moments in pp collisions at RHIC and LHC energies. By analyzing the results in the full phase space, it is found that the nonstatistical moments and moments products are significantly dependent on the collision energy. It is suggested that the net-proton nonstatistical moments in pp collisions may be studied in partial phase spaces with the PACIAE model. 相似文献
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The transverse momentum distributions of Λ's and proton's directed flows are investigated by using Quantum Molecular Dynamics model (QMD) within the framework of covariant kaon dynamics. The calculated results show that the transverse momentum distribution of differential directed flow of Lambda hyperons is dependent appreciably on the nuclear matter equation of states (EOS). The differential directed flow of Lambda hyperons calculated with soft EOS is consistent with the experimental data,whereas the discr... 相似文献
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We propose a forward method based on PYTHIA6.4 to study the jet properties in ultra-relativistic pp collisions.In the forward method,the partonic initial states are first generated with PYTHIA6.4 and then hadronized in the Lund string fragmentation model,and finally the hadronic jets are constructed from the created hadrons.Jet properties calculated with the forward method for pp collisions at √s=7 TeV are comparable to those calculated with the usual anti-kt algorithm(backward method)in PYTHIA6.4.The comparison between the backward and forward methods may contribute to the understanding of the partonic origin of jets in the backward method. 相似文献
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