1997 Vol. 21, No. 11
Display Method: |
The mean multiplicities of mesons π±、π0、K±、K0s、ρ0.K*0、K*±、φ and baryons p、Ξ±、Σ±(1385) are measured for the first time in J/ψ region with 200,000 J/ψ events collected by the BES detector. The results are compatible with LUND and Shandong phenomenological models. Based on the experimental results, the strangeness suppression factor s/u and spin suppression factor V/(V+P) are calculated to be ～0.3 and ～0.3—0.5 respectively, in good agreement with those given by ARGUS Collaboration in region. This indicates that the SU(6) breaking is consistent in the energy region from J/ψ to .
Both yrast and 4-quasiparticle bands in 162Lu are established by using in-beam spectroscopy. It is shown that within the framework of cranking shell model,positive deformation can also lead to the low-spin signature inversion in the yrast band in Z=71 odd-odd 162Lu nucleus.
The in-beam γ expedmental setup of HIRFL, which includes SFC(ECR ion source), direct-link-pipe(limit jaws) and in-beam γmeasurement system, was adjusted and tested with its first in-beam γ experiment. All performances, such as neutron and γ backgrounds of the setup have reached to an ideal level. With some special γ-ray spectroscopic techniques, the in=beam γ experiment, including γ single spectrtum. γ excitation funcdon, γ angular distdbudon and γ-γ-t coincidence measurements, was perfomned using reacdon 16O (197Au, xn).
With data collected by the Beijing Spectmmeter (BES) in the J/ψ,ψ′, and Ds energy region, a lot of e+e－ final state evenb are selected in the solid angle region covered by the endcap shower counters (ESC). Some characteristics of the ESC are analysed, such as the spectrnun of pulse height for, a single counter cell, the hit nwnbers in the ESC and in every reading layer of the ESC, the shower energies deposited in the ESC and in every layer of the BSC. The energy resoiudon of the ESC in obtained to be about 22%/E(GeV) Based on the odginal frame of SOBER, a Monte Carlo simulation program for the ESC is developed with a dual Gaussian pulse height spectrtun of the single counter cell. The electromagnetic cascades are calculated by the EGS4 package and a three-dimension magnetic field in the BES is included. The simulation results agree with experimented data well.
The angular dependence of the particle-Particle comeladon (PPC) and its asytiumeby (PPCA) have been calculated by using the experimental data of multiplicity production for pp collisions at 400GeV/ c. The results are different stmngly from the overall behavior of e+e－ data,but agree with the results obtained by NA22 collaboration quite well. The leading particles influence stingily the PPCA disribibudons for hadronic collisions data. The calculated results for the distributions of the azimuthal difference between two pardcles mean that the azimuthal correlation has been observed.
In this Paper, the Parameter ratio of (2+1)-D SU(2) 0++ glueball wavefunctionis calculated using scheme of truncating eigenvalus equations ,The result shows agood scaling behavior.
Two two-parameter deformed multi-mode boss operators which satisfy quantum Heisenberg-Weyl algebra are consbucted, and their algebraic structure. studied. As examples, the Holstein-Primokoff realizations for multi-node quantum. group SU(2)q,s. and SU(1,1)q,s are presented, and the eigenstates of the second power of the two-parameter deformed multi-mode bose operators are constructed, and their completenesses are proved.
We invesdgate the correction to the branching ratio of decay b→sγ from the Pseudo-Goldstone bosons (PGBs) in the multiscale walking technicolor model (MWTCM). Tbe correction is found so large that we can not explain the recentCLEO data lf topcolor is further introduced. the branching ratio in the topcolor assisted MWTCM will be in agreement with the CLEO data for a certain range of the model-allowed parameter space.
Using the Debye screening in QGP, the disbibudon function and the color electric potential of the quarks at high temperature, the radiated power of the rest color electric wave of the quarks in QGP are obtained. The relation between the radiated power of the rest color electric wave of the quarks and the Dedbye length λD is discussed. This will help to study the Debye screening potendal using the radiated Power.
Under different impact parameters, the collision system of 30MeV/u 40Ca+40Ca is investigated in terms of QltllD model. It is .shown that the number of IMFs is the largest at impact pararneter b=6fm, which is due to the formation of ＂neck＂ in collision process. Meanwhile, it is found the. in the process of fonmadon of ＂neck＂, the growth of the relative density fluctuation of the reaction system is very slow and the saturation value is small, which imply the character of shape instability.
The ground state correlation in model systems with different interaction strength and pardcle numbers has been studied. Nunnerical results tell us that if the ground state shape is quite stable, the ground state correlation can be approximately explained by the zero-point vibration based on the stadc ground state. It is rather important to carry out first the static self consistent field calculation. But around the critical point where the monopole deformation begins to occur, behaviors of the ground state conflation become very complicate and sensitive to the variation of controlling parameters. lt seems to indicate that particular attentions should be paid to ground state compilations in further studies of light nuclei near the drip line.
The inverse of the q-analogue boson creation and annihilation operators is introduced. By vimue of the properties of aq-1and aq+-1the q-analogue defomadon form of the Photostatted coherent states is constructed and its completeness relation is discussed.
Using the relativistic harmonic oscillator model, the helicity amplitudes of resonances are studied and the relativistic effect is addressed.
The particle-rotor model is applied to describe the odd A superdeformed nuclear states in A～150 mass region. The calculated ΔI=2 Staggering in superdeformed bands in 149Gd(bl) and 153Dy(bl) is compared with the observed data for the first time.
In proton linacs the pardcle beams are often focused by isochronic periodic fields, in which the lengths of periods are different but the times the particles travel through each period are constant. In this paper the basic theory of focusing by isochronic periodic fields is discussed. The theory can be generalized to the periodic fields with slow varying peridods.
Small strips of amorphous alloys Fe77.2Mn0.8Si9B13, Fe39Ni39V2Si12B8,Fe47Ni29V2Si6B16and Fe40Ni40Si12B8 have been irradiated with 2.79MeV/u Ar ions below 50K Using optical microscopy, the macroscopic. dimensions of the samples were measured at roomtemperature before and after irradiation The observed dimensional changes of all thesamples are very small for the low fluence of 1.5×1014ions/cm2, but it becomes drasticly large and irreversible when the fluence increased to 1.6×1015ions/cm2.Themeasured relative change in width Δb/b0 is in the range of 4.3%—12.0%.The results are qualitadvely discussed.
- A SCOAP3 participating journal - free Open Access publication for qualifying articles
- Average 24 days to first decision
- Fast-track publication for selected articles
- Subscriptions at over 3000 institutions worldwide
- Free English editing on all accepted articles
- The 2019 summer holiday-Office closure
- Editor Recruitment
- 2018 Impact Factor 5.861
- CPC Joins Committee on Publication Ethics (COPE)
- Chinese New Year-Office closure