1,215 research outputs found
Update of the stranger story: the strange vector form factors of the nucleon
The strange vector form factors are investigated in the framework of the semi-bosonized SU(3) Nambu-Jona-Lasinio model (or chiral quark-soliton model). The mean-square strange radius \langle r^2 \rangle_s=-0.17\; \mbox{fm}^2 and the strange magnetic moment \mu_s = -0.45 are obtained in case of the constituent quark mass M=420 \;\mbox{MeV}. The results are compared with several different models
Nucleon described by the chiral soliton in the chiral quark soliton model
We give a survey of recent development and applications of the chiral quark
soliton model (also called the Nambu-Jona-Lasinio soliton model) with =2
and =3 quark flavors for the structure of baryons. The model is an
effective chiral quark model obtained from the instanton liquid model of the
quantum chromodynamics. Mesons appear as quark-antiquark excitations and
baryons arise as non-topological solitons with three valence quarks and a
polarized Dirac sea. In this model, a wide variety of observables of baryons is
considered.Comment: A talk given in the international conference on "Quark Lepton Nuclear
Physics" in Osaka, Japan from May 20 to 23 in 1997. Proceedings will be
published in Nuclear Physics A. (5 pages + figures
Rotational Corrections to and Isovector Magnetic Moment of the Nucleon
The rotational corrections to the axial vector constant and the
isovector magnetic moment of the nucleon are studied in the Nambu --
Jona-Lasinio model. We follow a semiclassical quantization procedure in terms
of path integrals in which we can include perturbatively corrections in powers
of angular velocity . We find non-zero order
corrections from both the valence and the Dirac sea quarks. These corrections
are large enough to resolve the long-standing problem of a strong
underestimation of both and in the leading order. The axial
constant is well reproduced, whereas the isovector magnetic moment
is still underestimated by 25 \%.Comment: (Revtex), 10 pages (3 figures available on request), report
RUB-TPII-53/9
Strange and singlet form factors of the nucleon: Predictions for G0, A4, and HAPPEX-II experiments
We investigate the strange and flavor-singlet electric and magnetic form
factors of the nucleon within the framework of the SU(3) chiral quark-soliton
model. Isospin symmetry is assumed and the symmetry-conserving SU(3)
quantization is employed, rotational and strange quark mass corrections being
included. For the experiments G0, A4, and HAPPEX-II we predict the quantities
and . The dependence
of the results on the parameters of the model and the treatment of the Yukawa
asymptotic behavior of the soliton are investigated.Comment: 16 pages, 3 figures, Final version for publication in Eur. Phys. J.
ELISA: a cryocooled 10 GHz oscillator with 10-15 frequency stability
This article reports the design, the breadboarding and the validation of an
ultra-stable Cryogenic Sapphire Oscillator operated in an autonomous
cryocooler. The objective of this project was to demonstrate the feasibility of
a frequency stability of 3x10-15 between 1 s and 1,000 s for the European Space
Agency deep space stations. This represents the lowest fractional frequency
instability ever achieved with cryocoolers. The preliminary results presented
in this paper validate the design we adopted for the sapphire resonator, the
cold source and the oscillator loop.Comment: 13 pages, 10 figure
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