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1.
Abstract. We calculate the processes and to in the low-energy expansion of the standard model. The chiral amplitudes of can be extended via resonance exchange to energies around 1 GeV. Higher-order effects have been included in the form of and double exchange and by performing a resummation of the pion form factor. The predicted cross sections and the branching ratios are in good agreement with the available data.
Received: 8 March 2002 / Published online: 14 June 2002 相似文献
2.
R. Erdem 《The European Physical Journal C - Particles and Fields》2002,25(4):623-628
We give a simple model to explain the origin of fermion families and chirality through the use of a domain wall-anti-domain
wall pair placed in a five dimensional space-time.
Received: 14 March 2002 / Revised version: 3 July 2002 / Published online: 27 September 2002
RID="a"
ID="a" e-mail: erdem@likya.iyte.edu.tr 相似文献
3.
We prove the existence of correlations between the equilibrium states at different temperatures of the multi-p-spin spherical spin-glass models with continuous replica symmetry breaking: there is no chaos in temperature in these models.
Furthermore, the overlaps satisfy ultrametric relations. As a consequence the Parisi tree is essentially the same at all temperatures
with lower branches developing when lowering the temperature. We conjecture that the reference free energies of the clusters
are also fixed at all temperatures as in the generalized random-energy model.
Received 18 March 2002 / Received in final form 14 June 2002
Published online 1st October 2002
RID="a"
ID="a"e-mail: tommaso.rizzo@inwind.it 相似文献
4.
H.G. Dosch C. Ewerz V. Schatz 《The European Physical Journal C - Particles and Fields》2002,24(4):561-571
We study the odderon contribution to elastic pp and scattering at high energies. Different models for the odderon–proton coupling are considered and their effects on the differential
cross section in the dip region are investigated. We use a Regge fit by Donnachie and Landshoff as a framework and replace
its odderon contribution by the different models. We consider two models for the odderon–proton impact factor proposed by
Fukugita and Kwieciński and by Levin and Ryskin. In addition we construct a geometric model of the proton which allows us
to put limits on the size of a possible diquark cluster in the proton. All models are able to describe the data well. The
two models for the impact factor require the strong coupling constant to be fixed rather precisely. In the geometric model
a relatively small diquark size is required to describe the data.
Received: 1 February 2002 / Published online: 14 June 2002 相似文献
5.
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
6.
S. Bondarenko E. Levin J. Nuiri 《The European Physical Journal C - Particles and Fields》2002,25(2):277-286
We use the constituent quark model (CQM) to describe CDF data on double parton cross section and HERA data on the ratio cross section of elastic and inelastic diffractive productions. Our estimate shows that the radius of the constituent
quark turns out to be rather small, GeV-2, in accordance with the assumption on which CQM is based.
Received: 14 April 2002 / Published online: 9 August 2002 相似文献
7.
Hans Lindblad 《Communications in Mathematical Physics》2003,236(2):281-310
We study the motion of a compressible perfect liquid body in vacuum. This can be through of as a model for the motion of
the ocean or a star. The free surface moves with the velocity of the liquid and the pressure vanishes on the free surface.
This leads to a free boundary problem for Euler's equations, where the regularity of the boundary enters to highest order.
We prove linearized stability in Sobolev space assuming a ``physical condition', related to the fact that the pressure of
a fluid has to be positive.
Received: 23 September 2002 / Accepted: 2 December 2002
Published online: 14 April 2003
RID="⋆"
ID="⋆" The author was supported in part by the National Science Foundation.
Communicated by P. Constantin 相似文献
8.
E. Kraus Ch. Rupp K. Sibold 《The European Physical Journal C - Particles and Fields》2002,24(4):631-637
We study the Wess-Zumino model with the coupling extended to a chiral superfield. In order to incorporate the renormalization
effects a further external real field has to be introduced. It is then possible to derive a Callan-Symanzik equation and to prove renormalizability. By constructing
the supercurrent in this context the whole machinery for describing the superconformal symmetries becomes available. The presence
of the external fields allows also to define multiple insertions of all relevant composite operators. Interesting relations
to the curved superspace treatment show up.
Received: 12 April 2002 / Published online: 14 June 2002 相似文献
9.
Fabrice Planchon 《Communications in Mathematical Physics》2003,232(2):319-326
The Beale-Kato-Majda criterion asserts that smooth solutions to the Euler equations remain bounded past T as long as is finite, ohgr; being the vorticity. We show how to replace this by a weaker statement, on , where Δj is a frequency localization around .
Received: 27 February 2002 / Accepted: 29 July 2002 Published online: 14 November 2002 相似文献
10.
M. Kolář F. Slanina 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(3):379-384
We examine a model of biological evolution of Eigen's quasispecies in a so-called holey fitness landscape, where the fitness
of a site is either 0 (lethal site) or a uniform positive constant (viable site). The evolution dynamics is therefore determined
by the topology of the genome space which is modelled by the random Bethe lattice. We use the effective medium and single-defect
approximations to find the criteria under which the localized quasispecies cloud is created. We find that shorter genomes,
which are more robust to random mutations than average, represent a selective advantage which we call “topological”. A way
of assessing empirically the relative importance of reproductive success and topological advantage is suggested.
Received 9 August 2002 / Received in final form 7 November 2002 Published online 14 February 2003
RID="a"
ID="a"e-mail: slanina@fzu.cz 相似文献
11.
We theoretically investigated the mass dependence of the sympathetic cooling rate of gas-phase ions trapped in a linear radio-frequency-quadrupole
ion trap. Using an a priori molecular dynamical calculation, tracing numerically with Newtonian equations of motion, we found
that ions with a mass greater than 0.54±0.04 times that of the laser-cooled ions are sympathetically cooled; otherwise, they
are heated. To understand the mass dependence obtained using the molecular-dynamical calculation, we made a heat-exchange
model of sympathetic cooling, which shows that the factor of 0.54±0.04 is a consequence of absence of micro-motion along the
axis of the linear ion trap.
Received: 10 December 2001 / Revised version: 28 January 2002 / Published online: 14 March 2002 相似文献
12.
We study the static scalar susceptibility of the nuclear medium, i.e., the change of the quark condensate for a small modification of the quark mass. In the linear sigma model it is linked to
the in-medium sigma propagator and its magnitude increases due to the mixing with the softer modes of the nucleon-hole excitations.
We show that the pseudoscalar susceptibility, which is large in the vacuum, owing to the smallness of the pion mass, follows
the density evolution of the quark condensate and thus decreases. At normal nuclear matter density the two susceptibilities
become much closer, a partial chiral symmetry restoration effect as they become equal when the full restoration is achieved.
Received: 20 July 2002 / Accepted: 14 September 2002 / Published online: 21 January 2003
RID="a"
ID="a"e-mail: chanfray@ipnl.in2p3.fr
Communicated by A. Molinari 相似文献
13.
Continuous-wave tunable Cr2+:ZnS laser 总被引:1,自引:0,他引:1
I.T. Sorokina E. Sorokin S. Mirov V. Fedorov V. Badikov V. Panyutin A. Di Lieto M. Tonelli 《Applied physics. B, Lasers and optics》2002,74(6):607-611
We report the first continuous-wave tunable over ∼280 nm around 2.3 μm room-temperature operation of a chemical vapor transport-grown
and diffusion-doped Cr2+:ZnS laser, pumped by a Co:MgF2 laser at 1.67 μm and generating over 100 mW of output power at 16% slope efficiency. The self-consistent results of the laser
and spectroscopic analysis demonstrate a large potential of this crystal as an active medium for diode-pumped tunable mid-infrared
sources.
Received: 7 January 2002 / Revised: 14 March 2002 / Published online: 2 May 2002 相似文献
14.
We consider the Navier-Stokes equation on a two dimensional torus with a random force which is white noise in time, and excites
only a finite number of modes. The number of excited modes depends on the viscosity ν, and grows like ν
-3
when ν goes to zero. We prove that this Markov process has a unique invariant measure and is exponentially mixing in time.
Received: 14 March 2002 / Accepted: 7 May 2002 Published online: 22 August 2002 相似文献
15.
In the Ni–W system, a uniform amorphous Ni–W phase was obtained by ion irradiation of the nano-sized Ni–W multilayers at liquid-nitrogen
temperature. Interestingly, before undergoing complete amorphization, fractal patterns were observed at a relatively low irradiation
dose (3×1014 Xe+/cm2), and the patterns were characterized to consist of crystalline grains of Ni-enriched solid solution. The fractal dimension
was measured to be about 1.68±0.05, which was very close to that expected by the cluster diffusion-limited aggregation model.
Received: 30 January 2002 / Accepted: 2 February 2002 / Published online: 3 May 2002 相似文献
16.
We introduce a solid-on-solid growth process which evolves by random deposition of dimers, surface diffusion, and evaporation
of monomers from the edges of plateaus. It is shown that the model exhibits a robust transition from a smooth to a rough phase.
The roughening transition is driven by an absorbing phase transition at the bottom layer of the interface, which displays
the same type of critical behavior as the pair contact process with diffusion 2A↦3A, 2A↦.
Received 14 October 2002 Published online 14 February 2003
RID="a"
ID="a"e-mail: Haye.Hinrichsen@physik.uni-wuppertal.de 相似文献
17.
Superconducting quantum interference devices (SQUIDs) are very well suited for experimental investigations of ratchet effects.
This is due to the periodicity of the Josephson coupling energy with respect to the phase difference δ of the superconducting
macroscopic wave function across a Josephson junction. We show first that, within the resistively and capacitively shunted
junction model, the equation of motion for δ is equivalent to the motion of a particle in the so-called tilted washboard potential,
and we derive the conditions which have to be satisfied to build a ratchet potential based on asymmetric dc SQUIDs. We then
present results from numerical simulations and experimental investigations of dc SQUID ratchets with critical-current asymmetry
under harmonic excitation (periodically rocking ratchets). We discuss the impact of important properties like damping or thermal
noise on the operation of SQUID ratchets in various regimes, such as adiabatically slow or fast nonadiabatic excitation.
Received: 22 November 2001 / Accepted: 14 January 2002 / Published online: 22 April 2002 相似文献
18.
E. Horozov 《Communications in Mathematical Physics》2002,231(2):287-308
The aim of this paper is to solve the bispectral problem for bispectral operators whose order is a prime number. More precisely
we give a complete list of such bispectral operators. We use systematically the operator approach and in particular – Dixmier
ideas on the first Weyl algebra. When the order is 2 the main theorem is exactly the result of Duistermaat-Grünbaum. On the
other hand our proofs seem to be simpler.
Received: 14 February 2002 / Accepted: 10 June 2002 Published online: 21 October 2002 相似文献
19.
J. Ellis A. Kotzinian D.V. Naumov 《The European Physical Journal C - Particles and Fields》2002,25(4):603-613
We propose a model for the longitudinal polarization of baryons produced in deep-inelastic lepton scattering at any , based on static SU(6) quark-diquark wave functions and polarized intrinsic strangeness in the nucleon associated with individual valence quarks.
The free parameters of the model are fixed by fitting NOMAD data on the longitudinal polarization of hyperons in neutrino collisions. Our model correctly reproduces the observed dependences of the polarization on the kinematic variables. Within the context of our model, the NOMAD data imply that the intrinsic strangeness
associated with a valence quark has anticorrelated polarization. We also compare our model predictions with results from the
HERMES and E665 experiments using charged leptons. Predictions of our model for the COMPASS experiment are also presented.
Received: 25 May 2002 / Revised version: 8 June 2002 / Published online: 7 October 2002 相似文献
20.
F. Finkel D. Gómez-Ullate A. González-López M.A. Rodríguez R. Zhdanov 《Communications in Mathematical Physics》2003,233(2):191-209
The B
N
hyperbolic Sutherland spin model is expressed in terms of a suitable set of commuting Dunkl operators. This fact is exploited
to derive a complete family of commuting integrals of motion of the model, thus establishing its integrability. The Dunkl
operators are shown to possess a common flag of invariant finite-dimensional linear spaces of smooth scalar functions. This
implies that the Hamiltonian of the model preserves a corresponding flag of smooth spin functions. The discrete spectrum of
the restriction of the Hamiltonian to this spin flag is explicitly computed by triangularization. The integrability of the
hyperbolic Sutherland spin chain of B
N
type associated with the dynamical model is proved using Polychronakos's ``freezing trick'.
Received: 14 February 2002 / Accepted: 19 June 2002 Published online: 10 December 2002
RID="*"
ID="*" Corresponding author. E-mail: artemio@fis.ucm.es
RID="**"
ID="**" On leave of absence from Institute of Mathematics, 3 Tereschenkivska St., 01601 Kyiv-4 Ukraine
Communicated by L. Takhtajan 相似文献