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1.
Q2-evolution of the Bjorken sum rule in the resonance region is studied. The roles of the Roper resonance N* (1440) estimated by the constituent quark model and by the hybrid model are stressed. Moreover, the Q2- dependence of the Gerasimov-Drell-Hearn sum rule contributed by the resonances is also discussed.  相似文献   

2.
The exact analytical solution of the Klein-Gordon equation for the spin-0 particles in the generalized Woods-Saxon potential is presented. The bound state energy eigenvalues and corresponding wave functions are obtained in the closed forms. The correlations between the potential parameters and energy eigenvalues are examined for π0 particles.  相似文献   

3.
The spin structure of the nucleon can play a key testing ground for the Quantum Chromo-Dynamics(QCD) at wide kinematic ranges from smaller to large four momentum transfer Q 2. It is far more challenging to understand the QCD at small Q 2 region due to the non-perturbative nature. Jefferson Lab has been one of the major experimental facilities for the spin structure with its polarized electron beams and various polarized targets. A few QCD sum rules have been compared with the measured spin structure functions g 1 and g 2 at low Q 2 and the most surprising results have been obtained for the spin polarizabilities, γ 0 and δ LT .  相似文献   

4.
董宇兵 《中国物理 C》2001,25(8):720-724
利用夸克模型计算了核子的自旋相关结构函数随Q2的依赖关系.在小动量转移区研究高扭曲效应a2(Q2),d2(Q2)对结构函数的影响.计算结果和其它的一些模型理论计算做了比较.  相似文献   

5.
Exact solutions of the Dirac equation in the Robertson–Walker space-time are obtained by an elementary separation method that represents a straightforward improvement of previous results. The radial equations are integrated by reporting them to hypergeometric equations. The separated time equations are solved exactly for three models of universe expansion and integrated by series in a case of the standard cosmological model. The integration of both radial and time equations represents an improvement of previous results.  相似文献   

6.
In a 1977 paper of B. M. McCoy, C. A. Tracy and T. T. Wu there appeared for the first time the solution of a Painlevé equation in terms of Fredholm determinants of integral operators. Their proof is quite complicated. We present here one which is more straightforward and makes use of recent work of the author and C. A. Tracy.  相似文献   

7.
By using the extended Hirota‘s method, the N-soliton-like solution of the Ito equation is obtained. Furthermore, we also investigate the soliton-like solution interaction and find singularity.  相似文献   

8.
Based on a simple nonrelativistic constituent quark model, the nucleon structure function F2 in theresonance region is estimated by taking the contributions from low-lying nucleon resonances into account. Calculatedresults are employed to study quark-hardon duality in the nucleon electron scattering process by comparing them to thescaling behavior from the data in deep inelastic scattering region.  相似文献   

9.
By using the extended Hirota‘s method, the N-soliton-like solution of the Ito equation is obtained. Furthermore, we also investigate the soliton-like solution interaction and find singularity.  相似文献   

10.
The Navier-Stokes equation can be written in a form of Poisson equation. For laminar flow in a channel (plane Poiseuille flow), the Navier-Stokes equation has a non-zero source term (∇2u(x, y, z) = Fx (x, y, z, t) and a non-zero solution within the domain. For transitional flow, the velocity profile is distorted, and an inflection point or kink appears on the velocity profile, at a sufficiently high Reynolds number and large disturbance. In the vicinity of the inflection point or kink on the distorted velocity profile, we can always find a point where ∇2u(x, y, z) = 0. At this point, the Poisson equation is singular, due to the zero source term, and has no solution at this point due to singularity. It is concluded that there exists no smooth orphysically reasonable solutions of the Navier-Stokes equation for transitional flow and turbulence in the global domain due to singularity.  相似文献   

11.
为了研究Hirota方程的二阶怪波解和它在光纤中的传输特性,数值分析了二阶怪波的形成机理,并采用分步傅里叶方法数值模拟了二阶怪波在光纤中的传输特点.结果表明:二阶怪波可以看作两个怪波逐渐靠近的结果;在光纤中传输时,随着距离的增加,二阶怪波最终分裂成两组次波,每组次波的能量值降为初值的一半,它们之间的距离越来越大且互不干扰,并随着距离的增加能量逐渐降低.数值分析了自陡峭和自频移对二阶怪波传输的影响,发现自陡峭引起二阶怪波在传播过程中左波峰能量大于右波峰能量,自频移使怪波的中心发生了非线性偏离,且参数的正负决定偏离的方向.  相似文献   

12.
In this paper, some examples, such as iterated functional systems, scaling equation of wavelet transform,and invariant measure system, are used to show that the homoclinic orbit solutions exist in the functional equations too.And the solitary wave exists in generalized dynamical systems and functional systems.  相似文献   

13.
14.
A new method is used to obtain the anomalous dimension in the solution of the nonlinear diffusion equation.The result is the same as that in the renormalization group (RG) approach.It gives us an insight into the anomalous dimension in the solution of the nonlinear diffusion equation in the RG approach.Based on this discussion,we can see anomalous dimension appears naturally in this system.``  相似文献   

15.
We obtain solutions of the nonlinear Klein-Gordon equation using a novel operational method combined with the Adomian polynomial expansion of nonlinear functions. Our operational method does not use any integral transforms nor integration processes. We illustrate the application of our method by solving several examples and present numerical results that show the accuracy of the truncated series approximations to the solutions.  相似文献   

16.
In the present paper, we solve the radial parts of Dirac equation between the inner and the outer horizon in the Schwarzschild-de Sitter (SdS for short) geometry. Complete physical parameter space is divided into two regions depending on the height of the potential barrier and the energy of the incoming particle. In each region, we concentrate on two limiting cases. The first case is when the two horizons are close to each other and the second case is when the horizons are far apart. In each case, we give the semi-analytical solution by using WKB (Wentzel-Krames-Brillouin) approximation and show the instantaneous reflection and transmission coefficients as well as the radial wave functions graphically. PACS: 04.20.-q, 04.70.-s, 04.70.Dy, 95.30.Sf  相似文献   

17.
A new method - perturbative summation to infinite order is presented to obtain the anomalous dimension in the solution of the modified porous medium equation. The result is the same as that in the renormalization group (RG) approach. It gives us an insight into the anomalous exponent in the asymptotic solution of the modified porous medium equation in the RG approach. Based on this discussion, we can see that the anomalous dimension appears naturally in the problem and the nonlinearity reflects the anomalous long-time behavior of the system.  相似文献   

18.
A new method is used to obtain the anomalous dimension in the solution of the nonlinear diffusion equation.The result is the same as that in the renormalization group (RG) approach.It gives us an insight into the anomalous dimension in the solution of the nonlinear diffusion equation in the RG approach.Based on this discussion,we can see anomalous dimension appears naturally in this system.  相似文献   

19.
20.
A momentum-conserved Q2 evolution equation is obtained after the fusion process is included into the Altarelli-Parisi splitting-function argument.  相似文献   

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