## 1989 Vol. 13, No. S3

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**Abstract:**

We give here the one loop results of the numerical calculation and event generation of Bhabha scattering at LEP/SLC energy. EM radiative correction and hard collinear photon effect have been taken into consideration.

**Abstract:**

Charged particle multiplicity distributions in pp collisions at 400 GeV/c have been studied by using the LEBC films offered by CERN NA27 Collaboration. The corrections to the raw data are described. The results are compared with data at other energies. It shows that up to ISR energy the charged particle multiplicity distribution has KNO scaling behavior for non-single diffractive process, whereas for the inelastic process the distribution shows a deviation from KNO scaling.

**Abstract:**

The potential distribution in an electrostatic decelerating lens is calculated using the surface charge-density method, and then the Gill method is used to simulate the electron orbits. The resolution of the analyzer is calculated as 1.0 eV at 20 keV. The influence of the beam diameter, the injection angle and the hole diameter of the third electrode on the resolution is discussed. Some comments on the experimental data are given based on the simulation.

**Abstract:**

We present a variational calculation of the string tensions in (2 + l)-dimensional

*SU*(2) Lattice gauge theory using two kinds of Hamiltonians of which the exact ground states are known.

**Abstract:**

The variational-cumulant expansion method is generalized to the case of the lattice

*SU*(3) Wilson model. The plaquette energy as an order parameter is calculated to the 2nd order expansion. The result shows that the 1st order phase transition is not observed in the four-dimension case, which agrees with the result from the Monte Carlo calculation, but is clearly seen in the five-dimension case. This method can be used to study the problems in the lattice gauge theory with the

*SU*(3) gauge group.

**Abstract:**

The string tension of the infinite string in the lattice Schwinger model is precisely calculated with the Hamiltonian which has the solvable exact ground state. The result shows that in the lattice Schwinger model, one can obtain the linear confinement potential and no phase transition occurs when a approaches zero. This result coincides with that obtained in the continuum theory.

**Abstract:**

A modified lattice Schwinger model is proposed, the existence of the exact continuum limit proved and the exact ground state of the model found.

**Abstract:**

Based upon the consideration of the Fermi motion correction and the nuclear binding effect, the EMC effect can be explained by introducing the

*Q*

^{2}- and

*x*-rescaling mechanisms. The experimental data, especially in the region 0.2 <

*x*< 0.5, can be better reproduced by using the

*x*-rescaling mechanism than using the

*Q*

^{2}-rescaling mechanism. The problem of the nuclear momentum conservation in the EMC effect is further discussed. In order to make up the 4% nuclear momentum loss, the different

*Q*

^{2}- or

*x*-rescaling parameters for the momentum distributions of the valence and sea quarks in the nucleon structure function are chosen. The result shows that, by employing the extended

*x*-rescaling mechanism, a better agreement between the theoretical result and the experimental data in the small

*x*region can be obtained.

**Abstract:**

Using the Maximum Entropy Method(MEM), we investigated the high energy limit in hadron-hadron collisions. Different kinds of entropies are defined and the role of physical constraints in maximizing the entropy is emphasized. Definite prediction for the average multiplicity in high energy limit and the interpolation between this limit and the existing data are obtained.

**Abstract:**

By using the Jastrow correlation wave function, the role of nucleon-nucleon short-range correlations in the nuclear structure function in the

*x*>1 region is reanalyzed. The result shows that with the proper energy-momentum distribution of nucleons in the nucleus including the effect of nucleon-nucleon short-range correlations, the experimental data of the nuclear structure function in the

*x*>1 region could not be well explained. It seems that additional components which go beyond the conventional nuclear physics are necessary to describe the effect.

**Abstract:**

The Boltzmann-Uehling-Uhlenbeck (BUU) equation, which is the time evolution of time Wigner function of the single particle Green's function, is derived by using the closed-time Green's function approach. The quantum mechanical approximation in deriving time BUU equation is discussed.

**Abstract:**

The cross sections of the evaporation residues from the bombardment of 52-71 MeV

^{12}C ion on

^{112}Sn have been measured by means of

*γ*-ray detection. The residues have been transported from inside of the target chamber to the detection port by using a special device, and detected by a Ge(Li) detector. Only the relative cross sections have been obtained.

**Abstract:**

Resonant structures appearing in the excitation functions of the

^{16}O+

^{20}Ne elastic scattering have been studied by using the nuclear molecular orbit theory. The theoretical results agree well with the experimental data.

**Abstract:**

In view of the proton boson and neutron boson coupling, all possible dynamical symmetries in the proton-neutron interacting boson model (IBM2) are discussed. The symmetries are found to be in four types, of which some are newly discovered. The commonly used IBM2 computer code NPBOS is checked through the group-chain method. It shows that most results of the NPBOS calculations are correct except the case in which O

_{x}·O

_{x}and O

_{v}·O

_{v}are included in the Hamiltonian. Using a modified NPBOS,the energy levels and E2 transitions of

^{150}Sm and

^{152}Sm are studied.

**Abstract:**

Using the method of Green's function and partial summation of multiple scattering, we have investigated in various approximations the contribution of 2p-1h multiple scattering correlation to the low energy spectrum of

^{17}O and

^{15}O, respectively. In our calculation, the nuclear force employed is the Paris potential and the energy dependence of G matrices has been taken into account rigorously. The numerical results agree with the experimental data reasonably well.

**ISSN** 1674-1137 **CN** 11-5641/O4

Original research articles, Ietters and reviews Covering theory and experiments in the fieids of

- Particle physics
- Nuclear physics
- Particle and nuclear astrophysics
- Cosmology

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