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991.
A constituent quark model is developed for an arbitrary light-cone direction so that the light-front time is xLF+ = ω · x with a constant lightlike four-vector ω. Form factors are obtained from free one-body electromagnetic current matrix elements. They are found to be ω-independent for spin-0 mesons, nucleons and the Λ-hyperon, while there is an ω-dependence for spin-1 systems like the deuteron. 相似文献
992.
本文推出了平均值的包含因子与测量次数n的正确关系,计算了两组实验结果的置信水准,纠正了文[1]的两个错误,得出了评定实验结果的一般结论。 相似文献
993.
Various symmetry relations developed between neutrino-neutron and antineutrino-proton elastic scattering cross sections are
surveyed and an identity between scattering amplitudes and a symmetry between cross sections of these processes established
by consideringCPT andG conjugation invariance of current matrix elements. A symmetry is obtained giving rise to a theorem on the nature of contribution
of form factors to terms in the cross sections. 相似文献
994.
A general method of obtaining wavefunctions for empirical diatomic molecular potential functions has been given. Efficacy
of the method has been tested by computing Franck-Condon factors for some bands of a new system of SiO using Morse oscillator
model and these have been compared with the ones obtained using exact Morse wavefunctions. It is concluded that the method
is satisfactory at low quantum numbers. 相似文献
995.
Bojan Magajna 《Proceedings of the American Mathematical Society》2001,129(3):771-780
Each weak* compact C-convex set in a hyperfinite factor (in particular in ) is the weak* closure of the C-convex hull of its C-extreme points.
996.
Bo-Wen Xiao Xin Qian Bo-Qiang Ma 《The European Physical Journal A - Hadrons and Nuclei》2002,15(4):523-527
The electromagnetic form factor of the kaon meson is calculated in the light-cone formalism of the relativistic constituent
quark model. The calculated K+ form factor is consistent with almost all of the available experimental data at low-energy scale, while other properties
of the kaon could also be interrelated in this representation with reasonable parameters. Predictions of the form factors
for the charged and neutral kaons at a higher-energy scale are also given, and we find the non-zero K0 form factor at Q
2≠ 0 due to the mass difference between the strange and down quarks inside K0.
Received: 21 June 2002 / Accepted: 29 July 2002 / Published online: 3 December 2002
RID="a"
ID="a"e-mail: mabq@phy.pku.edu.cn
Communicated by A. Sch?fer 相似文献
997.
Let
be the Dirichlet integral and
the Brownian motion on R. Let be a finite positive measure in the Kato class and
the additive functional associated with . We prove that for a regular domain D of R
d
where
D
is the exit time from D. As an application, we consider the integrability of Wiener functional exp (
). 相似文献
\beta )\;\; = \;\; - \inf \left\{ {\tfrac{1}{2}D(u,u):u \in C_0^\infty (D)\int_D {u^2 {\text{d}}} \mu = 1} \right\} \hfill \\ {\text{ for any }}x \in D, \hfill \\ \end{gathered} $$ " align="middle" vspace="20%" border="0"> |
998.
Explicit evaluation of the following parameters has been carried out in the extraU (1) superstring inspired model: (i) As Mz2 varies from 555 GeV to 620 GeV and (m
t) CDF = 175.6 ± 5.7 GeV (Table 1): (a) SNew varies from -0.100 ± 0.089 to -0.130 ± 0.090, (b) TNew varies from -0.098 ± 0.097 to -0.129 ± 0.098, (c) UNew varies from -0.229 ± 0.177 to -0.253 ± 0.206, (d) Τz varies from 2.487 ± 0.027 to 2.486 ± 0.027, (e) ALR varies from 0.0125 ± 0.0003 to 0.0126 ± 0.0003, (f) A
FB
b
remains constant at 0.0080 ± 0.0007. Almost identical values are obtained for (m
t)D0 = 169 GeV (see table 2). (ii) Triple gauge boson vertices (TGV) contributions: AsMz
2 varies from 555 GeV to 620 GeV and (m
t) CDF = 175.6 ±5.7 GeV. (a)√s = 500 GeV, asymptotic case:
varies from -0.301 to -0.179;
varies from -0.622 to -0.379;
varies from +0.0061 to 0.0056;
varies from -3.691 to -2.186.
varies from +0.270 to +0.118;
varies from +0.552 to 0.238;
varies from +0.0004 to +0.0002;
remains constant at -0.110. (b)√s = 700 GeV, asymptotic case:
varies from -0.297 to -0.176;
varies from -0.609 to -0.370;
varies from -0.0082 to -0.0078;
varies from -3.680 to -2.171.√s = 700 GeV, nonasymptotic case:
varies from -0.173 to -0.299;
varies from-0.343 to -0.591;
varies from -0.005 to -0.011;
remains constant at -0.110.
The pattern of form factors values for√s = 1000, 1200 GeV is almost identical to that of√s= 700 GeV. Further the values of the form factors for (m
t)D0 (=169 GeV) follow identical pattern as that of (m
t) CDF form factors values (see tables 5, 6, 9, 10).
We conclude that the values of all the form factors with the exception of these of
,
are comparable or larger than theS, T values and therefore the TGV contributions are important while deciding the use of extraU (1) model for doing physics beyond standard model. 相似文献
999.
Treating the coulomb interaction between ion species as a perturbation on the Waisman-Lebowitz solution for direct correlation
function within the hard core region, the total direct correlation function in K-space has been formulated, which gives a
direct method of evaluating the partial structure factors between different ion species of the fused salts through the use
of Pearson-Rushbrooke equations. The partial structure factors so obtained have been applied to evaluate the partial radial
distribution functions of ion pairs. In addition, many other important associated functions such as the static correlations
of total number, mass and charge densities have been computed by particular linear combination of partial structure factors.
The charge neutrality relate the partial structure factors to the isothermal compressibility for the wavevectorK → 0 and hence the evaluation of the compressibilities of ions in fused KBr is possible, which agrees well with the observed
value. As such the present method is very useful in investigating the structure of molten salts since only the parametersσ
ij
, the distances of closest approach between ions andɛ, the effective dielectric constant (which can be estimated from the literature) are enough for this work. 相似文献
1000.
U.T. Yakhshiev U.-G. Meißner A. Wirzba 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):569-574
We investigate the possible modifications of the nucleons' electromagnetic form factors in the framework of a modified Skyrme
model allowing for nucleon deformation and using realistic nuclear mass distributions. We show that such effects are small
in light nuclei
Received: 19 November 2002 / Accepted: 3 December 2002 / Published online: 18 March 2003
RID="a"
ID="a"Address after January 1st, 2003: Helmholtz Institut für Strahlen- und Kernphysik (Theorie), Universit?t Bonn, Nu?allee
14-16, D-53115 Bonn, Germany; e-mail: meissner@itkp.uni-bonn.de
RID="b"
ID="b"Present address: Helmholtz Institut für Strahlen- und Kernphysik (Theorie), Universit?t Bonn, D-53115 Bonn, Germany.
Communicated by V. Vento 相似文献