By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the J/ψ ＂normal nuclear absorption＂ and energy loss effects are studied in a GIauber formalism at HE...By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the J/ψ ＂normal nuclear absorption＂ and energy loss effects are studied in a GIauber formalism at HERA and RHIC energies. Assuming that the absorption cross section σabs increases with the charmonium-nucleon center of mass energy, the results reveal a significant dependence of the aabs on rapidity g at RHIC energies. The initial-state energy loss effect, which is found important only at HERA energies, is also considered, and its influence should be eliminated when we studied the absorption effect at low collision energies. Finally, we also present the theoretical prediction for LHC.展开更多
The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity...The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.展开更多
The nucleon electromagnetic form factors are investigated within a simple diquark-quark model using the light-front formalism. In this model, baryon is described as a bound state of one quark and one clustering diquar...The nucleon electromagnetic form factors are investigated within a simple diquark-quark model using the light-front formalism. In this model, baryon is described as a bound state of one quark and one clustering diquark. The calculational results are compared with the experimental ones. We also regard the quarks in a baryon as pointlike constituent quarks.展开更多
文摘By means of the nuclear parton distribution studied only with lepton deep-inelastic scattering experimental data, the J/ψ ＂normal nuclear absorption＂ and energy loss effects are studied in a GIauber formalism at HERA and RHIC energies. Assuming that the absorption cross section σabs increases with the charmonium-nucleon center of mass energy, the results reveal a significant dependence of the aabs on rapidity g at RHIC energies. The initial-state energy loss effect, which is found important only at HERA energies, is also considered, and its influence should be eliminated when we studied the absorption effect at low collision energies. Finally, we also present the theoretical prediction for LHC.
基金The project supported by National High Technique Development Project (863) No.2002AA843130Scientific Fund of CAEP No. 20030214
文摘The propagation of a supersonic heat-wave through copper-doped foam with a density of 50 mg/cm^3 was experimentally investigated. The wave is driven by 140 eV Holhraum radiations generated in a cylindrical gold cavity heated by a 2 kJ, ins laser pulse （0.35 μm）. The delayed breakout time of the radiation waves from the rear side of the foam is measured by a three-chromatic streaked x-ray spectrometer （TCS） consisting of a set of three-imaging pinholes and an array of three transmission gratings coupled with an x-ray streak camera （XSC）. With one shot, simultaneous measurements of the delays of the drive source and the radiation with two different energies （210 eV, 840 eV） through the foam have been made for the first time. The experimental results indicate that the time delays vary with photon energies. The radiation with an energy of 210 eV propagates at a lower velocity. The radiating heat wave propagates with a velocity that is larger than the sound speed. Using TGS, the transmitting spectrum was measured, and then lower limit of the optical depth which is more than 1, was obtained. The experimental data were in agreement with numerical simulations.
基金The project supported by the Natural Science Foundation of Hebei Province of China under Grant No. A2005000535
文摘The nucleon electromagnetic form factors are investigated within a simple diquark-quark model using the light-front formalism. In this model, baryon is described as a bound state of one quark and one clustering diquark. The calculational results are compared with the experimental ones. We also regard the quarks in a baryon as pointlike constituent quarks.
