CAS Lanzhou Institute of Modern Physics

Lanzhou, China

CAS Lanzhou Institute of Modern Physics

Lanzhou, China
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He J.,CAS Lanzhou Institute of Modern Physics | He J.,Lanzhou University | He J.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

Very recently, two hidden-charmed resonances Pc(4380) and Pc(4450) consistent with pentaquark states were observed at the LHCb detector. The two Pc states locate just below the D-σc* and D-*σc thresholds with mass of gaps about 5 and 15 MeV, respectively. Inspired by this fact we perform a dynamical investigation about the D-σc*(2520) and D-*σc(2455) interactions which are described by the meson exchanges. A bound state which carries spin-parity JP=3/2- is produced from the D-σc*(2520) interaction, which is consistent with the Pc(4380) observed at the LHCb detector. From the D*σc(2455) interaction, a bound state with 5/2+ is produced, which can be related to the Pc(4450). The results suggest that the Pc(4380) and Pc(4450) are good candidates of D-σc*(2520) and D-*σc(2455) molecular states, respectively. © 2015.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2013

Subthreshold kaon (K0 and K+) production in neutron-rich nuclear reactions to probe the kaon-nucleon interaction in nuclear medium and to extract the isospin-dependent part of the nuclear equation of state at high-baryon densities is investigated within an isospin- and momentum-dependent transport model. A repulsive kaon-nucleon potential is implemented in the model through fitting the flow data and inclusive spectra in heavy-ion collisions, which enhances the energetic kaon emission squeezed out in the reaction zone and leads to a variation of the high-momentum spectrum of the K0/K+ yields. It is found that the stiffness of nuclear symmetry energy plays a significant role on the isospin ratio with decreasing the incident energy and a hard symmetry energy has a larger value of the K0/K+ ratio in the domain of subthreshold energies. © 2013 American Physical Society.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Nuclear Physics A | Year: 2013

Strangeness (K0, +, Λ and σ -,0, +) production in heavy-ion collisions near threshold energies has been investigated within the Lanzhou quantum molecular dynamics (LQMD) transport model. The kaon (antikaon)-nucleon and hyperon-nucleon potentials in dense nuclear matter are implemented in the model, which are computed from the chiral perturbation approach and the relativistic mean-field model, respectively. It is found that the in-medium potentials change the structure of transverse flow, and also affect the rapidity distributions and the inclusive spectra for strangeness production. The local temperature of the fire ball extracted from the kaon spectra of inclusive invariant cross sections is influenced by the kaon-nucleon potential. The stiffness of nuclear symmetry energy and the kaon-nucleon potential by distinguishing isospin effect play a significant role on the ratio of K0/K +, in particular at the subthreshold energies. The ratio of σ -/σ + depends on the high-density symmetry energy, in which the σ-nucleon potential has a neglectable contribution on the isospin ratio. © 2013 Elsevier B.V.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2011

A Skyrme-type momentum-dependent nucleon-nucleon force distinguishing isospin effect is parametrized and further implemented in the Lanzhou quantum molecular dynamics model, which leads to a splitting of nucleon effective mass in nuclear matter. Based on the isospin- and momentum-dependent transport model, we investigate the influence of momentum-dependent symmetry potential on several isospin-sensitive observables in heavy-ion collisions. It is found that symmetry potentials with and without the momentum dependence but corresponding to the same density dependence of the symmetry energy result in different distributions of the observables. The midrapidity neutron/proton ratios at high transverse momenta and the excitation functions of the total π-/π+ and K0/K+ yields are particularly sensitive to the momentum dependence of the symmetry potential. © 2011 American Physical Society.


Wang J.,CAS Lanzhou Institute of Modern Physics
Cell death & disease | Year: 2013

Cellular responses to DNA damage induced by intrinsic and extrinsic genotoxic stresses are highly regulated by complex signaling pathways, such as activation of the phosphoinositide-3-kinase-like protein kinase family and their downstream genes. Disruption of these signaling pathways leads to genome instability and cell death, and thus may provide potential novel strategies for cancer therapy. Here, we find that the expression of a human microRNA (miRNA), hsa-miR-185, is downregulated in response to ionizing radiation. Elevation of miR-185 sensitizes renal cell carcinoma cells to X-rays both in vitro and in vivo. Bioinformatic analysis shows that the ATM- and Rad3-related (ATR) kinase, a master conductor of cellular responses to DNA damage and DNA replication stresses, is a target of miR-185. This prediction was validated by luciferase reporter and mutation assays. We also demonstrated that miR-185 negatively regulates ATR expression at post-transcriptional level. miR-185 enhances radiation-induced apoptosis and inhibition of proliferation by repressing ATR pathway. In conclusion, our findings indicate a previously unreported regulatory mechanism for ATR expression mediated by miR-185 and shed light on the potential application of miRNAs both as direct cancer therapeutics and as tools to sensitize tumor cells to radiotherapy.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2011

The dynamics of pions and strange particles in heavy-ion collisions in the region of 1A GeV energies is investigated by the lanzhou quantum molecular dynamics model for probing the nuclear equation of state at suprasaturation densities. The total multiplicities and the ratios obtained in Au197 +197Au over C12+12C systems are calculated for selected Skyrme parameters SkP, SLy6, Ska, and SIII, which correspond to different modulus of incompressibility of symmetric nuclear matter and different cases of the stiffness of symmetry energy. A decreasing trend of the excitation functions of the ratios for strange particle production with increasing incident energy was observed. The available data of K+ production measured by KaoS collaboration are described well with the parameter SkP, which results in a soft equation of state. The conclusions cannot be modified by an in-medium kaon-nucleon potential. © 2011 American Physical Society.


Yong G.-C.,CAS Lanzhou Institute of Modern Physics
Physical Review C - Nuclear Physics | Year: 2011

Based on an isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model, effects of high-density behavior of nuclear symmetry energy in the proton-rich reaction 22Si+22Si at a beam energy of 400 MeV/nucleon are studied. It is found that the symmetry energy affects π+ production more than π-. More interestingly, compared to neutron-rich reactions, for π-/π+ and dense matter's N/Z ratios, effects of symmetry energy in the proton-rich reaction show contrary behaviors. The practical experiment by using the proton-rich reaction 22Si+40Ca to study nuclear symmetry energy is also provided. © 2011 American Physical Society.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Transverse emission of preequilibrium nucleons, light clusters (complex particles) and charged pions from the isotopic Sn112,124+Sn112,124 reactions at a beam energy of 400 A MeV, to extract the high-density behavior of nuclear symmetry energy, are investigated within an isospin and momentum-dependent transport model. Specifically, the double ratios of neutron/proton, triton/helium-3 and π -/π + in the squeeze-out domain are analyzed systematically, which are favorable in reducing the influence of the Coulomb force and less systematic errors. It is found that the transverse momentum distribution of isospin ratios strongly depend on the stiffness of nuclear symmetry energy, which would be a nice observable to extract the high-density symmetry energy. The collision centrality and the mass splitting of neutron and proton in nuclear medium play a significant role on the distribution structure of the ratios, but do not change the influence of symmetry energy on the spectrum. © 2011 Elsevier B.V.


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics
Nuclear Physics A | Year: 2012

Within the framework of an isospin and momentum dependent transport model, the emissions of isospin particles (nucleons and light clusters) squeezed out in heavy-ion collisions are investigated as probes of the poorly known symmetry energy at high baryon density. Two different mass splittings of neutrons and protons in nuclear medium as mn*>mp* and mn*


Feng Z.-Q.,CAS Lanzhou Institute of Modern Physics | Jin G.-M.,CAS Lanzhou Institute of Modern Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2010

Within the framework of the improved isospin dependent quantum molecular dynamics (ImIQMD) model, the emission of pion in heavy-ion collisions in the region 1 A GeV as a probe of nuclear symmetry energy at supra-saturation densities is investigated systematically, in which the pion is considered to be mainly produced by the decay of resonances Δ (1232) and N* (1440). The total pion multiplicities and the π- / π+ yields are calculated for selected Skyrme parameters SkP, SLy6, Ska and SIII, and also for the cases of different stiffness of symmetry energy with the parameter SLy6. Preliminary results compared with the measured data by the FOPI Collaboration favor a hard symmetry energy of the potential term proportional to (ρ / ρ0)γs with γs = 2. Crown Copyright © 2009.

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