Proton-deuteron elastic scattering at intermediate and high energies illustrates the importance of the phase variation of the nucleon-nucleon elastic scattering amplitude as in previous work. Two kinds of phase variation are examined. The first is the usual one which is related to free nucleon-free nucleon collisions as suggested by Franco. The second is assumed to be related to the time ordering of multi-scattering processes. The two kinds play similar roles in improving the results. The contributions of both kinds lead to a good fit to the experimental data at the energies considered. The value of the phase variation parameter in each kind (where they are considered together), which gives a good fit to the experimental data, are approximately the same and of order 4 (GeV/ c) -2. Also, with relatively small values of the phase variation parameter, the phase variation effect improves the agreement with the experimental data for the p-4He elastic scattering differential cross section at the minimum region in the energy range 97-393 GeV.

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Using a representation of the quark distribution inside the proton, where a short-range correlation between quarks is considered, we can describe the p-p elastic scattering differential cross section with experimental agreement in the range 0 :::; q2 :::; 10 (GeV/ c)2. Evaluations of the proton core and quark radii are obtained. From our analysis, we see that the suggested configuration of quarks inside the proton can be considered as a nearly realistic distribution even with a non-relativistic wavefunction.

Proton-'He elastic scattering is studied within the framework of the Glauber approximation at 1 GeV. The short-range correlations and the three-body force effects are studied. These effects are wnsidered through a ground state wavefunction of the target nuclew. The results are discussed and compared with experimental data.

In this paper, we employ the energy surface method to study a system of a two-level atom Bose–Einstein condensate coupled to a high-finesse optical cavity interacting with a single-mode electromagnetic field in the presence of the Stark-shift. The energy surface, the Phase transitions and the Berry phase of the two-level atom in Dicke model are obtained. Employing the Holstein–Primakoff representation of the angular momentum Lie algebra, the coupling line separation of the normal phase and the superradiant phase which occurs in a collection of fluorescent emitters (such as atoms), between a state containing few electromagnetic excitations are studied and a mean field description of the Dicke model is presented. We notice that in the thermodynamic limit, the energy surface takes a simple form for a direct description of the phase transition. Moreover, we show that the Stark-shift parameters and the atom–atom interactions can strongly affect the phase transition point. The results in the absence of the Stark-shift agree precisely with those obtained by Li, Liu and Zhou, who studied the same model using a different method.