首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
In this paper,we suggest that the gluon is hadronized by first splitting into a quark-anti-quark pair.The final hadrons are produced by the color interactions among the quarks and antiquarke.By this assumption,the calculated average charged particle multiplicities in e+e→3jet events,and the ratio of multiplicities between gluon and quark jet,and the rates of baryons in e+e three gluons events all agree well with experiments.The angle distribution of final particles can be explained.  相似文献   

2.
In this note,we discuss the cross-sections of the production of Υ particles in p-p collisions as color excited states in the Han-Nambu model.The results are consistent with present experiments.  相似文献   

3.
Angular distribution of the scattering of 31.2 MeV-α-particle by the nucleus 10,11B is measured. Our results show that there is anomalous phenomenon in the case of 10B but there is not in 11B. Calculations and analysis are made with the optical model adding the Regge-Pole model. The results show that for the nucleus of 1p-shell, such as α+16O, the result of the calculation agrees very well with the experimental measurements but it fails in α+10B. As to the analysis with the double v-power optieal model for α+16O, the agreement is somewhat a little worse than the former's and the result for α+10B agrees only qualitatively with the experimental measurement. It is well known that the analysis with these models for α+40Ca agrees very well with the experimental data. Thus we may come to the conclusion that the mechanism of ALAS of the nucleus of 2s-1d shell is different from that of 1p-shell, and the mechanisms of ALAS of the nuclei of 1p-shell are also different.  相似文献   

4.
The effects of Pb doping, oxygen doping (δ= 0.1,0.2,0.4 and 0.5) and high pressate (4, 8, 15 and 20GPa) on the electronic structure of Hg0.8Pb0.2Ba2Ca2Cu3O8+δ have been examined by the recursion method. Our calculations show that Pb doping only decreases the hole concentration slightly and oxygen doping increases the hole concentration monotonically and significantly as δ varies from 0 to 0.5, with each excess oxygen atom contributing about 1.7 holes to the CuO2 layers. The optimal δ is estimated to be around 0.4, The hole conceatration increases initially with pres-sure but decreases as P > 8GPa (i.e., dn/dP does change sign at ~ 8GPa). The suppressed Tc(P) by Pb substitution has to be described in the modified Neumeier's model.  相似文献   

5.
The optical-optical double resonant multiphoton ionization (OODR-MPI) technique and the fluorescent excitation spectroscopy technique have been applied to the study of the F′0+u ion-pair state of iodine. This paper presents OODR-MPI spectrum and fluorescent excitation spectrum of I2 in the region of 54000-55300cm-1 by the three-photon resonant, two-photon ionization (1+2+2) and (1+(1+1)+2) processes.  相似文献   

6.
The Fourier transform spectrum of the ν2+2ν3 band of the HDO molecule was recorded with a resolution of 0.02 cm-1. The spectrum was rotational analysed and the spectroscopic parameters of the (0,1,2) state were estimated in terms of Watson's effective rotational Hamiltonian model and also the model in the Padé-Borel approximation form. They reproduce the upper energy levels with an accuracy close to the experimental uncertainty of 0.001 cm-1.  相似文献   

7.
A formalism for studying the interference between the direct reaction and the compound resonance processes is presented by the S-matrix theory; The mechanism of 12C(d, d) 12C, 12C(d, p113C* and 12C(d, p213C* reactions in the energy range Ed=1.63 MeV to 2.05 MeV is analysed.Te results show that: the interference between these two processes exists; and the quantitative relation between them is given. While the parameters of direct reactions and compound resonance processes, particularly for four resonance states with Ed=1.726, 1.767, 1.792 and 1.86 MeV are determined.  相似文献   

8.
The energy spectra and angular distributions of the emitted α particles in the reactions of the 69.5MeV 12C bombarding 12C,27Al and natCa have been measured and analysed using the fast particle exciton model. The contribution from the equilibrium and preequilibrium α-emissions is calculated to be 89%, 81% and 83% of the total α yields for the three reactions respectively, where the preequilibrium α emissions are 11%, 14% and 16% respectively. A small contribution comes from the other reaction mechanism.  相似文献   

9.
This paper presents systematically the doping effects of halogens in YBa2Cu3O7-δ polycrystalline samples, with a series of concentrations of fluorine, chlorine, bromine or iodine. All samples were prepared by chemical method of citrate pyrolysis, which makes the halogen concentration in the samples more uniform. Samples doped with F have Tc as high as 94.5K, Cl, Br and I dopings also raise Tc to a certain extent. In addition, the influence of halogen doping on critical current density, morphology, constitution and so forth is discussed.  相似文献   

10.
11.
We show that the near correlation in rapidity is consistent with the requirements of QCD, and completely determines the combination rule of quarks. We give the formulae for calculating yields of mesons, baryons and antibaryons, which are produced by a stochastic accumulation of quarks with similar rapidities. Using it to e+e annihilation, the observation of recently unexpected copious production of baryons is explained naturally.  相似文献   

12.
In this paper the DWBA cross section formula for the(π+,d)reaction is deri-ved in the model of one-nucleon absorption of pion,and the differential cross sectionsfor 12C(π+,d)10Cg.5.2+reactions are estimated in PWBA.This kind of reaction isregarded as a worthnoting one for the studies of π absorption processes and the nu-clear pair structure.  相似文献   

13.
In this paper we work out the relativistic covariant B-S wave function for the(π+ π-s atoms.Some properties of the“direct channel diagram”of the produc-tion the (π+ π-s atoms are discussed by calculating the cross-section of the process π+ +np+(π+ π-s with the help of the relativistic covariant wave function and assuming the lowest termin the perturbation expansion series of the quantized composite field theory——the“direct channel diagram”is dominant.Besides this calcuation perhaps presentsa rough estimate for the interesting process μ+ +n→(μ+ π-)+p.  相似文献   

14.
The energy spectra and angular distributions of alpha particles emitted in the reaction of 12C on 209Bi in the energy range 61.1—73.0 MeV were observed.The △E— E detector system was used to separate alpha particles and other particles emitted in this reaction.The results can be interpreted in terms of the reaction mechanism,in which a 8Be cluster is transfered from the projectile to the target.Good agreement has been obtained between the cross section for the production of the direct alpha particles and that of the heavy residue 217*Fr which,left in the ground state after evaporation of 2 neutron's,decays into 211At by alpha emission.The experimental energy spectra and angular distributions have been fitted by a semi-classical formula for the differential cross section per unit solid angle and energy interval.  相似文献   

15.
Radiative transition in δ-doped GaAs superlattices with and without Al0.1Ga0.9As barriers is investigated by using photoluminescence at low temperatures. The experimental results show that the transition mechanism of δ-doped superlattices is very different from that of ordinary superlattices. Emission intensity of the transition from the electron first excited state to hole states is obviously stronger than that from the electron ground state to hole states due to larger overlap integral between wavefunctions of electrons in the first excited state and hole states. Based on the effective mass theory we have calculated the self-consistent potentials, optical transition matrix elements and photoluminescence spectra for two different samples. By using this model we can explain the main optical characteristics measured. Moreover, after taking into account the bandgap renormalization energy, good agreement between experiment and theory is obtained.  相似文献   

16.
Photoemission measurements have been carried out for Bi2Sr2CaCu2-xSnxO8+δ system with conventional x-ray photoemission spectroscopy for core-level spectra and synchrotron radiation photoemission spectroscopy for valence band. With Sn doping, all core levels shift differently in binding energy, and the intensity near fermi energy becomes smaller in valence hand. From the experiment, we can deduce that the shifts of all core levels and valence hands may involve some other mechanisms, such ms electrostatic effects, in addition to binding energy referencing effects. We argue that the chemical environment plays a crucial role in the electronic structure of high-temperature superconductors.  相似文献   

17.
Hadronic production of J/ψψ′(3684) particles is discussed in this paper on thebasis of reference [1] after considering the massive effects of the charmed straton.The results of [1] are improved.With the aid of the decay of ψ″→DD and the effective coupling constant between ψ″(3772) and the charmed straton we estimate that the content of the charmed stratonin the sea of the stratons is 0.41% of the ordinary stratons at most.  相似文献   

18.
The photorefractive effects of the as-grown and proton-implanted KNbO3 crystals were studied by two-wave mixing at 62.2μW/cm2 illumination. At this pump power level, the as-grown crystal showed little photorefractive effect, while the proton-implanted crystal showed an obvious effect. Furthermore, there seemed to exist two photorefractive gratings with response times of 22.54 and 1596.30s, at 62.2μW/cm2 pump power level, in the proton-implanted sample. This phenomenon has been attributed to the influence of proton-implantation.  相似文献   

19.
刘道志 《中国物理》1995,4(10):778-782
We describe the results of Haman studies on C=C stretch modes in α-ET3(ReO4)2 charge-transfer salt with the incident laser beam polarised perpendicular and parallel to the large flat face of plate-like crystal. We have assigned central C=C stretch mode at 1454 cm-1 and ring C=C stretch mode at 1470cm-1. The change in ring C=C stretch vibration was observed at the metal-insulator transition of α-ET3(ReO4)2 on warming due to the distortion of the ET molecules.  相似文献   

20.
蔡震  金学军 《中国物理》1998,7(12):912-918
Secondary ion mass spectroscopy was used to study the chemical diffusivity of 018 in c-textured YBa2Cu3O7-δ/SrTiO3 epitaxial thin film. By fitting experimental data to the one- dimensional diffusion curve, the apparent diffusivity along the c-axis was obtained to be equal to l.02×1014cm2/sec when the temperature was 350℃. A computer analysis method was put forward to calculate the "spiral diffusion" process, and the diffusivity anisotopy of films with different mosaic size obtained. For a film of 7000×7000?2 mosaic size, Dab was found to be ~3.55×10-5xexp((-1.03 ev)/kT) cm2/sec. The calculated results reveal that the variation of the results of Dc is not the result of diffusivity anisotropy but of the difference in mosaic size.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号